Thinking Inside the Box

29 Jul 2014•In the News, Research Protocol

It’s difficult to determine how these things get started—how the results of a well-documented experiment conducted nearly 40 years ago become twisted into the frequently made—and widely-accepted—claim that “even well-fed cats hunt.”

This would appear to be a case of validity through repetition: repeat a claim often enough and, eventually, people will come to believe it’s true—never bothering to check the original source. (Pro Tip: For added efficacy, click the heels of your ruby-red slippers together while repeating the claim.)

This, it should go without saying, is not how science is supposed to work. Read more

HAHF-Truths, HAHF-Measures, Full Prices (Part 1)

24 Aug 2012•In the News, Trap-Neuter-Return

Complaining of the impacts of free-roaming cats on wildlife and the environment, along with a range of public health threats, dozens of veterinarians in Hillsborough County, Florida, have banded together to fight TNR. Evidence suggests, however, that their real concern has nothing to do with the community, native wildlife, or, indeed, with cats. What the Hillsborough Animal Health Foundation is most interested in protecting, it seems, is the business interests of its members.

This was Take Your Cat to the Vet Week, a time “to raise awareness of the fact that cats need an annual veterinarian examination just as much as dogs,” according to Feline Pine, the litter manufacturer responsible for the occasion’s creation. In Hillsborough County, Florida, however, it was a time for many in the veterinary community to reiterate their opposition to TNR.

“We love cats!” Don Thompson assured me earlier this week via e-mail. “Any person who argues that vets don’t love animals is being foolish.” But, just like David Aycock, chief animal control officer for Pompano Beach, Thompson’s love has its limits—feral cats need not apply.

Thompson’s not a vet himself, but an attorney. He, along with his veterinarian wife, Katie, operate the Veterinary Center at Fishhawk, and he’s also head of the Hillsborough Animal Health Foundation, whose members are, according to the HAHF website, “gravely concerned about Trap-Neuter-Return (TNR).” Read more

The Annotated Apocalypse Meow

16 Apr 2012•In the News

In the current issue of The Washingtonian, senior writer Luke Mullins provides the most comprehensive profile yet of former Smithsonian researcher Nico Dauphiné, convicted last October of attempted animal cruelty. Most telling are his conversations with her unwavering supporters, who—in spite of the evidence, her well-documented history, and her miserable performance on the stand—continue to make excuses for her.

In the five months since she was convicted of attempted animal cruelty, former Smithsonian researcher Nico Dauphiné has enjoyed a respite from the largely unflattering media spotlight. All that changed in the past few weeks, though—first with Conservation magazine’s “Cat Fight,” and now with a 6,100-word feature in the April issue of The Washingtonian.

In “Apocalypse Now,” senior writer Luke Mullins digs into Dauphiné’s DC court case, as well as her previous “community service” in Athens, GA. The Nico Dauphiné that emerges is a far cry from the sympathetic character portrayed in “Cat Fight”—where, for example, writer John Carey laments: “Unfortunately, the strange case of the accused cat poisoner didn’t end well.” [1]

Although Mullins was unable to speak with Dauphiné for the piece, his conversations with people close to Dauphiné—as well as many who observed her mistreatment of cats—are illuminating. Read more

Spoiler Alert

6 Jun 2011•In the News, Legal Issues, Policy Issues, Threats to Wildlife

Coming up this Wednesday: “Impacts of Free Roaming Cats on Native Wildlife,” a Webinar sponsored by the U.S. Fish and Wildlife Service. Registration, from what I can tell, appears to be open to the public—though I’m still awaiting a confirmation e-mail (which will include, I hope, some clarification re: time zone for this “2:00–3:00 pm” event).

The USFWS Website lists the agency’s own Tom Will as the scheduled speaker, and includes the following description:

A rapidly growing feral and unrestrained domestic cat population kills an average of at least 1.5 million birds in the U.S. every day—and even greater numbers of small mammals and herptiles. Every small songbird species is vulnerable at some stage of its life cycle. Despite ample peer-reviewed science documenting the failure of trap-neuter-release (TNR) programs to reduce cat populations or address wildlife depredation, TNR and outdoor cat feeding colonies continue to be marketed to city councils, county boards, and state legislatures as a viable option. As a result, TNR feeding colonies are proliferating across the landscape at such an alarming rate that wildlife conservation programs intended to create source habitat are being rendered ineffectual in many areas. In this presentation, I briefly review the science on the effects of outdoor cats on wildlife and the ineffectiveness of TNR programs. Then, examples of the decision making process leading to community endorsement of TNR provide some insight into the roadblocks to effective conservation action. Finally, I offer a suite of strategic conservation actions at national agency, community, and home scales whereby the Service and its partners might work effectively to reduce the negative effects of irresponsible civic TNR decisions on wildlife trust resources.

I expect, given Will’s apparent interest in the science surrounding this issue, that he’ll shed some light on the origins of that 1.5 million birds/day predation rate—which, translated to an annual figure, is pretty close to what the American Bird Conservancy uses in The American Bird Conservancy Guide to Bird Conservation: “532 million birds killed annually by outdoor cats.” [1]

This Webinar, then, could be our chance to see the science behind the number. Or not—if this week’s presentation is anything like the one Will gave in 2010 to the Bird Conservation Alliance (which, according to its Website, is “facilitated by” ABC). Last year’s show, “What Can Federal Agencies Do? Policy Options to Address Cat Impacts to Birds and Their Habitats,” available (downloadable PDF) via the Animal Liberation Front Website, was short on science and long on rhetoric (and plenty of misinformation, too).

Now, I’ve no way of knowing what Will is going to present this week. So, although these things tend to be remarkably predictable, I’ll reserve judgment.

That said, it seems like a good time for a quick look at his 2010 material.

Birds of a Feather
As it happens, Tom Will is among those Nico Dauphine thanks “for helpful information, advice, ideas, and discussion in researching this subject” in her 2009 Partners In Flight conference paper. [2] And much of the material Will used last year was shown a year earlier by Dauphine, in her infamous “Apocalypse Meow” presentation. (The similarities are uncanny, actually: identical background color, many of the same images, etc.)

Death by (Faulty) Statistics
Like Dauphine, Will includes the graph (shown below) from the second edition of Frank Gill’s Ornithology, suggesting, apparently, that predation by cats far exceeds all other sources of mortality combined (a claim Dauphine made in her 2008 letter to the editor of the St. Petersburg Times).

Figure 24-4--Human-related causes of mortality (Gill's Ornithology)

But, as I’ve explained previously, Gill’s cat “data” aren’t data at all, but the indefensible (in terms of its lack of scientific merit, but also its almost palpable bias) guesswork of Rich Stallcup, co-founder of the Point Reyes Bird Observatory.

All of which raises serious doubts about USFWS’s commitment “to using sound science in its decision-making and to providing the American public with information of the highest quality possible.”

Counting Cats
The more intriguing visual, though, in Will’s 2010 presentation (shown below) is meant (it seems) to illustrate the relationship between the increasing population of cats and the decreasing populations of bird species over the past 40 years or so.

But, of course, correlation is not the same as causation. I’ll bet that, like cat ownership, membership in the National Audubon Society has risen steadily over the past 40 years—but somehow, I don’t imagine anybody suggesting that bird populations decline as NAS membership climbs.

What first caught my eye was not the the implied relationship between cat numbers and bird numbers, however, but the red dots themselves. The same data were plotted (as shown below) in “What Conservation Biologists Can Do to Counter Trap-Neuter-Return: Response to Longcore et al.,” [3] published last year in Conservation Biology, (among the paper’s 10 co-authors, by the way: Nico Dauphine and Peter Marra).

What Conservation Biologists Can Do--Chart_590px

Look closely at the two graphs, and you’ll see that Will has gotten creative here. His data points (which, I believe, come primarily from the U.S. Census and APPA) are identical to those used in the letter to Conservation Biology, but the vertical scale’s been changed. In Will’s version, the upper right portion of the graph has jumped from 90 million to 150 million cats! (His horizontal axis is shifted slightly, but the impact is nothing by comparison.)

Apparently, Will is combining population data for pet cats with data for feral cats. Trouble is, his “data” for feral cats doesn’t exist. It looks as if Will simply borrowed from Dauphine, who borrowed from David Jessup—whose “estimate” is unattributed.

So much for “using sound science” and “providing the American public with information of the highest quality possible.”

Roaming Charges May Apply
What if Will stuck to what the data actually show? It seems the message is pretty clear: since 1971, the number of pet cats in the U.S. has nearly tripled.

OK, but what does that mean for the nation’s wildlife? Keep in mind: the country’s human population swelled by 43 percent over the same period, taking an enormous toll on wildlife—either directly (e.g., loss of habitat via development, birds colliding with buildings, etc.) or indirectly (e.g., increased pollution and pesticide use).

Let’s set all that aside for the moment, though, and get back to pet cats. Even if the graphs accurately reflect the upward trend of cat ownership in the U.S. (and I’m not sure they do), they grossly misrepresent the threat to wildlife—which, presumably, is the point.

Simply put, there are not three times as many pet cats outdoors today.

The data I have, from the American Pet Products Association, [4] go back only to 1998. At that time, 56 percent of cat owners responding to APPA’s National Pet Owners Survey indicated that their cats were indoors-only; in 2008, that figured had climbed to 64 percent.

With an estimated 89.6 million pets cats in the U.S. in 2010, then, that means that about 32.4 million cats are outdoors for at least some part of the day (and approximately half of those are outside for less than three hours each day [5, 6]).

What was the proportion in 1971? Unfortunately, I’ve been unable to find any survey results from the 1970s or 1980s. All we can do it guess.

Let’s say that in 1971 just one-third of pet cats were kept indoors exclusively (the very situation Dauphine would have us believe we’re facing today). That means 21.5 million cats were free-roaming for at least some part of the day.

Again, this is a guess—not an unreasonable one, but a guess anyhow. Still, the implications are significant. While it’s true that the number of pet cats has tripled over the past 40 years, the number that are free-roaming has probably increased by only 50 percent or so.

Prosecution or Persecution?
Finally, I’m curious to see if Will’s “suite of strategic conservation actions” will include, as his 2010 presentation suggests, threatening those who conduct or officially endorse TNR with prosecution under the Endangered Species Act (ESA) and the Migratory Bird Treaty Act (MBTA).

This has become a common tactic in recent years (see, for example, the Florida Keys National Wildlife Refuges Complex Integrated Predator Management Plan/Draft Environmental Assessment, released earlier this year), though it goes back to at least 2003, when Pamela Jo Hatley, then a law student, suggested the possibility.

(One wonders if USFWS, the agency responsible for drafting the Keys Predator Management Plan, could be prosecuted under the ESA and MBTA in the event—not unlikely—that a large-scale round-up of feral cats resulted in a population explosion of rats, which in turn decimate the very species the Plan claims to protect.)

• • •

As a say, I’m not going to critique Will’s presentation until he’s had the chance to give it. Indeed, he may very well deliver on the science review, policy insights, conservation actions, etc. If what he provided the BCA is any indication, though, the man’s got his work cut out for him.

Literature Cited
1. Lebbin, D.J., Parr, M.J., and Fenwick, G.H., The American Bird Conservancy Guide to Bird Conservation. 2010, London: University of Chicago Press.

2. Dauphine, N. and Cooper, R.J., Impacts of Free-ranging Domestic Cats (Felis catus) on birds in the United States: A review of recent research with conservation and management recommendations, in Fourth International Partners in Flight Conference: Tundra to Tropics. 2009. p. 205–219. http://www.pwrc.usgs.gov/pif/pubs/McAllenProc/articles/PIF09_Anthropogenic%20Impacts/Dauphine_1_PIF09.pdf

3. Lepczyk, C.A., et al., “What Conservation Biologists Can Do to Counter Trap-Neuter-Return: Response to Longcore et al.” Conservation Biology. 2010. 24(2): p. 627–629. www.abcbirds.org/abcprograms/policy/cats/pdf/Lepczyk-2010-Conservation%2520Biology.pdf

4. APPA, 2009–2010 APPA National Pet Owners Survey. 2009, American Pet Products Association: Greenwich, CT. http://www.americanpetproducts.org/pubs_survey.asp

5. Clancy, E.A., Moore, A.S., and Bertone, E.R., “Evaluation of cat and owner characteristics and their relationships to outdoor access of owned cats.” Journal of the American Veterinary Medical Association. 2003. 222(11): p. 1541-1545. http://avmajournals.avma.org/doi/abs/10.2460/javma.2003.222.1541

6. Lord, L.K., “Attitudes toward and perceptions of free-roaming cats among individuals living in Ohio.” Journal of the American Veterinary Medical Association. 2008. 232(8): p. 1159-1167. http://www.avma.org/avmacollections/feral_cats/javma_232_8_1159.pdf

Apocalypse Meow: A Brief Review

3 Jun 2011•Cats and Birds, In the News, Legal Issues

Although Nico Dauphine has yet to be suspended from her duties at the Smithsonian’s Migratory Bird Center, it seems all the attention she’s received over the past week-and-a-half is making life rather uncomfortable for her supporters.

Last week, the National Zoo removed Dauphine’s online application for recruiting field assistants from its Website; this week, the University of Georgia’s Warnell School of Forestry and Natural Resources pulled her infamous “Apocalypse Meow” presentation from its site.

Which is understandable, given the circumstances. Far more puzzling is what it was doing there in the first place. The content is, not surprisingly, remarkably “selective” in terms of the science. What is surprising, though, is Dauphine’s delivery: she looks and sounds like a person without the least bit of conviction in the material she’s presenting. (Actually, she’s mostly reading to the audience—for 41 minutes.)

Dauphine (whose status hearing, originally scheduled for June 1, has been postponed until the 15th) presented “Apocalypse Meow: Free-ranging Cats and the Destruction of American Wildlife” in March of 2009, at Warnell (where she earned her PhD). Although she tells the audience that her goal “is to review and present the best available science that we have,” what she delivers is essentially no different from what she presented in her Partners In Flight conference paper [1] (much of which is recycled in the current issue of The Wildlife Professional in a special section called “The Impact of Free Ranging Cats” [2]).

In other words: lots of exaggerated and misleading claims—and plenty of glaring omissions (i.e., the distinction between compensatory and additive predation).

Included in the section on predation are all the usual suspects: Longcore et al., [3] Coleman and Temple, [4] Crooks and Soulé, [5] PhD dissertations by both Christopher Lepczyk [6] and Cole Hawkins, [7] along with references to Linda Winter, David Jessup, [8] Pamela Jo Hatley, and others.

Among the highlights:

Invasive Species (of All Kinds)
Referring to island extinctions, Dauphine references a 2008 paper by Dov Sax and Steven Gaines—the same one the U.S. Fish and Wildlife Service cite (again, as “evidence” of island extinctions caused by cats) in their Florida Keys National Wildlife Refuges Complex Integrated Predator Management Plan/Draft Environmental Assessment, released earlier this year. As I point out in my response to the Keys plan, though, the Sax & Gaines paper isn’t about cats at all, but invasive plants. [9]

Magic Multipliers
For Dauphine, Lepczyk’s estimated 52 birds/cat/year predation rate simply isn’t enough. Studies using “prey returns,” she argues, underestimate the real damage. “Some studies using radio-collars and other techniques have shown that, typically, cats will return maybe one in three kills that they make, and sometimes not at all—so this is, again, a very conservative estimate of the actual number of kills.”

But Lepczyk’s PhD work wasn’t based on “prey returns” at all. He used a survey (one of many flaws), asking landowners, “how many dead or injured birds a week do all the cats bring in during the spring and summer months?” [6]

And the idea that cats return only one in every three kills? That’s based on some wonky analysis by Kays and DeWan, who studied the hunting behaviors of just 24 cats: 12 that returned prey home, and another 12 (11 pets and 1 feral) that were observed hunting for a total of 181 hours (anywhere from 4.8–46.5 hours per cat). [10]

The Selective Generalist
Dauphine stretches Hawkins’ conclusions (which Hawkins himself had already stretched past the point of being defensible) to suggest “a sort of preferential prey take for native species in some cases, by cats.” In other words, the cats might target native species.

Or not. Less than two minutes later, Dauphine’s making the case for hyperpredation—the devastating impact on native prey species (e.g., seabirds) brought about by a large population of cats supported largely by predation on an introduced prey species (e.g., rabbits).

From Millions to Billions
It’s difficult not to see Dauphine’s assertion that “it’s not productive to argue about the numbers”—which comes fairly early in her presentation—as disingenuous when she tries repeatedly to quantify predation levels (each of which is then qualified as “conservative”). Her use of a graph included in the second edition of Frank Gill’s Ornithology (shown below) is particularly interesting.

Now, the original source of Gill’s cat “data,” as Dauphine acknowledges, is Rich Stallcup’s 1991 article, “A reversible catastrophe”—inexplicably, the only source Gill cites when he refers to predation by cats: “Domesticated cats in North America may kill 4 million songbirds every day, or perhaps over a billion birds each year (Stallcup 1991). Millions of hungrier, feral (wild) cats add to this toll…” [11]

And where does Stallcup’s “data” come from?

“He simply argued—he didn’t do a study—he just argued that if one in ten of those cats kills one bird per day, already then we have 1.6 billion cat-killed birds per year,” explains Dauphine. “We actually know that the numbers are much larger. For instance, he’s starting out with 55 million pet cats; we know there are over 100 million outdoor cats in this country, and possibly far more. We also know from some studies that 80 percent of cats hunt, and the number of birds killed per year are probably much higher. So again, just to emphasize: this is a conservative estimate.”

In fact, Stallcup’s “estimate” is even flimsier than Dauphine suggests:

“Let’s do a quick calculation, starting with numbers of pet cats. Population estimates of domestic house cats in the contiguous United States vary somewhat, but most agree the figure is between 50 and 60 million. On 3 March 1990, the San Francisco Chronicle gave the number as 57.9 million, ‘up 19 percent since 1984.’ For this assessment, let’s use 55 million.

Some of these (maybe 10 percent) never go outside, and maybe another 10 percent are too old or too slow to catch anything. That leaves 44 million domestic cats hunting in gardens, marshes, fields, thickets, empty lots, and forests.

It is impossible to know how many of those actively hunting animals catch how many birds, but the numbers are high. To be very conservative, say that only one in ten of those cats kills only one bird a day. This would yield a daily toll of 4.4 million songbirds!! Shocking, but true—and probably a low estimate (e.g., many cats get multiple birds a day).” [12]

Shocking, yes. True? Why would anybody think so? (I can see the appeal for Dauphine, though: like her, Stallcup grossly overestimates the number of pet cats allowed outdoors.)

(The fact that this absurdity made it—however well disguised—into a standard ornithology textbook may explain a great deal about the positions frequently taken by today’s wildlife managers and conservation biologists regarding feral cats/TNR.)

Apocalypse Now
Perhaps the strangest—almost surreal—part of “Apocalypse Meow” comes when, to illustrate her point that the (over)heated TNR debate can “result in a lot of misunderstandings, misinformation, and hard feelings,” Dauphine refers to an e-mail sent out to the university’s CATSONCAMPUS listserv during the fierce TNR debate in Athens, which read in part:

“There are some folks in the area (and all over) who are not only Anti-TNR, they also hate felines so much that some of them want to round up the cats in the area and kill them.”

Two years later, this is pretty much what Nico Dauphine stands accused of.

Literature Cited
1. Dauphine, N. and Cooper, R.J., Impacts of Free-ranging Domestic Cats (Felis catus) on birds in the United States: A review of recent research with conservation and management recommendations, in Fourth International Partners in Flight Conference: Tundra to Tropics. 2009. p. 205–219. http://www.pwrc.usgs.gov/pif/pubs/McAllenProc/articles/PIF09_Anthropogenic%20Impacts/Dauphine_1_PIF09.pdf

2. Dauphine, N. and Cooper, R.J., “Pick One: Outdoor Cats or Conservation.” The Wildlife Professional. 2011. 5(1): p. 50–56.

3. Longcore, T., Rich, C., and Sullivan, L.M., “Critical Assessment of Claims Regarding Management of Feral Cats by Trap-Neuter-Return.” Conservation Biology. 2009. 23(4): p. 887–894. http://www.abcbirds.org/abcprograms/policy/cats/pdf/Management_claims_feral_cats.pdf

4. Coleman, J.S. and Temple, S.A., “Rural Residents’ Free-Ranging Domestic Cats: A Survey.” Wildlife Society Bulletin. 1993. 21(4): p. 381–390. http://www.jstor.org/pss/3783408

5. Crooks, K.R. and Soulé, M.E., “Mesopredator release and avifaunal extinctions in a fragmented system.” Nature. 1999. 400(6744): p. 563–566. http://www.nature.com/nature/journal/v400/n6744/abs/400563a0.html

6. Lepczyk, C.A., Mertig, A.G., and Liu, J., “Landowners and cat predation across rural-to-urban landscapes.” Biological Conservation. 2003. 115(2): p. 191–201. http://www.sciencedirect.com/science/article/B6V5X-48D39DN-5/2/d27bfff8454a44161f8dc1ad7cc585ea

7. Hawkins, C.C., Impact of a subsidized exotic predator on native biota: Effect of house cats (Felis catus) on California birds and rodents. 1998, Texas A&M University

8. Jessup, D.A., “The welfare of feral cats and wildlife.” Journal of the American Veterinary Medical Association. 2004. 225(9): p. 1377-1383. http://www.ncbi.nlm.nih.gov/pubmed/15552312

http://www.avma.org/avmacollections/feral_cats/javma_225_9_1377.pdf

9. Sax, D.F. and Gaines, S.D., Species invasions and extinction: The future of native biodiversity on islands, in In the Light of Evolution II: Biodiversity and Extinction,. 2008: Irvine, CA. p. 11490–11497. www.pnas.org/content/105/suppl.1/11490.full

http://www.pnas.org/content/105/suppl.1/11490.full.pdf

10. Kays, R.W. and DeWan, A.A., “Ecological impact of inside/outside house cats around a suburban nature preserve.” Animal Conservation. 2004. 7(3): p. 273-283. http://dx.doi.org/10.1017/S1367943004001489

www.nysm.nysed.gov/staffpubs/docs/15128.pdf

11. Gill, F.B., Ornithology. 2nd ed. 1995, New York: W.H. Freeman and Company.

12. Stallcup, R., “A reversible catastrophe.” Observer 91. 1991(Spring/Summer): p. 8–9. http://www.prbo.org/cms/print.php?mid=530

http://www.prbo.org/cms/docs/observer/focus/focus29cats1991.pdf

It’s Not the Media, It’s the Message

19 Mar 2011•In the News, The Cat Debate, Threats to Wildlife

To hear The Wildlife Society’s staunch opponents of TNR tell it, the media’s just not interested in stories about “the impacts of free-ranging and feral cats on wildlife.”

“This January when thousands of blackbirds fell from the sky in Arkansas, articles about mass extinctions and bird conservation were a dime-a-dozen. When the Deepwater Horizon oil spill killed 6,000 birds between April to October 2010, news organizations ran ‘Breaking News’ about the negative impacts on the environment. Meanwhile it is estimated that one million birds are killed everyday by cats, and the only news organizations covering it are small, local branches. The bigger problem is being shuffled to the backburner for more sensational news.”

According to The Wildlife Society (TWS), however, “the bigger problem” is “greater than almost any other single-issue.”

In their effort to get the issue on the front burner, TWS has “gathered the facts about these cats, and published them in the Spring Issue of The Wildlife Professional in a special section called ‘The Impact of Free Ranging Cats.’” (available free via issuu.com)

Thus armed, readers are expected to, as it says on the cover, “Pick One: Outdoor Cats or Conservation”

Back Burner or Hot Topic?
Before we get to the “facts,” it’s worth looking back over the past 15 months to see just how neglectful the media have been re: “the bigger problem.”

January 9, 2010: Travis Longcore, science director for the Urban Wildlands Group, tells Southern California Public Radio: “Feral cats are documented predators of native wildlife. We do not support release of this non-native predator into our open spaces and neighborhoods, where they kill birds and other wildlife.”

January 17, 2010 Longcore, whose Urban Wildlands Group was lead plaintiff in a lawsuit aimed to put an end to publicly supported TNR in Los Angeles, tells the L.A. Times: “It’s ugly; it’s gotten very vicious. It’s not like we’ve got a vendetta here. This is a real environmental issue, a real public health issue.” In the same story, American Bird Conservancy’s Senior Policy Advisor, Steve Holmer, tells the Times: “The latest estimates are that there are about . . . 160 million feral cats [nationwide]… It’s conservatively estimated that they kill about 500 million birds a year.”

May 8, 2010: Austin American-Statesman writer Mike Leggett devoted his column to the defense of his cat-killing neighbor. According to Leggett, the man’s killed more than 20 feral cats—he “just cannot tolerate what cats do to wild birds.” And, offers Leggett, “none of us should.”

June 17, 2010: An Associated Press story about a proposed feeding ban in Barre, VT, (subsequently picked up by MSNBC) includes multiple quotes from ABC’s Cats Indoors! campaign.

September 10, 2010: Jonathan Franzen, winner of the 2001 National Book Award and a Pulitzer Prize finalist the following year—also an ABC board member—tells Studio 360 host Kurt Andersen that housecats kill a million songbirds a day, just as Franzen depicts in his latest novel Freedom. “Minimum, minimum,” insists Franzen. “Cats should be indoors.”

September 30, 2010: “Scientists are quietly raging about the effects that cats, both owned and stray, are having on bird populations,” claims Washington Post columnist Adrian Higgins. “It’s not an issue that has received much attention, but with an estimated 90 million pet cats in the United States, two-thirds of them allowed outdoors, the cumulative effect on birds is significant, according to experts.” Higgins’ story is riddled with misinformation, courtesy of the American Bird Conservancy (ABC), The Wildlife Society, and Dauphine and Cooper’s 2009 Partners in Flight paper.

October 2010: The Smithsonian Migratory Bird Center posts “Baby Catbird Survival” on its Website (the page is currently “under renovation”), claiming that cats were responsible for “alarmingly high rates of nest predation and fledging [sic] mortality.”The evidence? It seems “several guilty-looking cats were found in close proximity to dead birds. Our guess is that closer examination would have revealed feathers in their whiskers.”

December 20, 2010: Feral cats are included among “The World’s Worst Invasive Mammals,” as determined by the Smithsonian (which, by the way, has yet to approve my comment). The article’s misinformation is as sensational as its headline: “In addition to carrying rabies, 62 to 82 percent of cats in a recent study tested positive for toxoplasmosis.”

December 2010: “Feral Cats and Their Management” is picked up by numerous media outlets, many of which mistake it for actual research.

January 17, 2011: Toronto Star reporters do the dirty work for TNR opponent David Bird (“The more cats, the fewer birds”) and Maureen Palmer, director of the recently released documentary Cat Crazed:

“Palmer said one of the most ‘heartbreaking’ scenes during filming was at a volunteer spay-neuter clinic in Los Angeles that sterilized 80 ferals a day. She said most of the cats had infections that never healed, as well as broken bones, large abscesses around their teeth and mange.” (A claim easily discredited, if only the reporters had bothered to check.)

January 2011: Utah Representative Curtis Oda sponsors HB 210, which would permit “the humane shooting of an animal in an unincorporated area of a county, where hunting is not prohibited, if the person doing the shooting has a reasonable belief that the animal is a feral animal.”

March 7, 2011: Once again, the Smithsonian is promoting Peter Marra’s gray catbird research. Among the first to pick it up is Discovery News. Two days later, the story is featured on Science at the Smithsonian, “a new Website from the Smithsonian Office of Public Affairs.”

Yet, the folks at TWS would have us believe that “the only news organizations covering [the cat-bird issue] are small, local branches.” As is often the case, their story doesn’t hold up well alongside the facts.

Indeed, other than when Higgins got Executive Director/CEO Michael Hutchins’ name wrong, it’s hard to see what TWS has to complain about.

The Art of Selling Science
“After years of arguments,” laments Nico Dauphine and Robert Cooper, recalling last year’s decision by Athens, GA, to adopt TNR, “the vote was cast: 9–1 in favor of the ordinance, with an additional 7–3 vote establishing a $10,000 annual budget to support the TNR program.”

“How could this happen in a progressive community like Athens, Georgia, home to one of the nation’s finest university programs in wildlife science? The answer is a complex mix of money, politics, intense emotions, and deeply divergent perspectives on animal welfare… If we’re going to win the battle to save wildlife from cats, then we’ll need to be smarter about how we communicate the science.” [1]

Something tells me this “smarter” communication doesn’t allow for much in the way of honesty and transparency—attributes already in short supply.

Old Habits
“The Impact of Free Ranging Cats” has given its contributors the opportunity to revive and reinforce a range of dubious claims, including the ever-popular exaggerations about the number of free-roaming cats in the environment.

According to Dauphine and Cooper, “The number of outdoor pet cats, strays, and feral cats in the U.S. alone now totals approximately 117 to 157 million,” [1] an estimate rooted in their earlier creative accounting. Colin Gillin, president of the American Association of Wildlife Veterinarians, who penned this issue’s “Leadership Letter” (more on that later), follows suit, claiming “60 million or more pet cats are allowed outdoors to roam free.” [2]

The American Pet Products Association 2008 National Pet Owners Survey, though, indicates that 64 percent of pet cats are indoor-only during the daytime, and 69 percent are kept in at night [3]. Of those that are allowed outdoors, approximately half are outside for less than three hours each day. [4, 5]

This information is widely available—and has been for years—yet many TNR opponents continue to inflate by a factor of two the number of free-roaming pet cats.

And it only gets worse from here.

Dense and Denser
Not content to inflate absolute cat numbers, Dauphine and Cooper go on to misrepresent research into population demographics as well. “Local densities can be extremely high,” they write, “reaching up to 1,580 cats per square kilometer in urban areas.” [1] In fact, the very paper they cite paints a rather different picture. For one thing, there’s quite a range involved: 132–1,579 cats per square kilometer (a point recognized by Yolanda van Heezik, another contributor to the special issue [6].)

Also, this is a highly skewed distribution—there are lots of instances of low/medium density, while high densities are far less common. As a result, the median (417) is used “as a measure of central tendency” [7] rather than the mean (856). So, although densities “reaching up to 1,580 cats per square kilometer in urban areas” were observed, more than half fell between 132 and 417 cats per square kilometer (or 51–161 cats per square mile).

Even more interesting, however, are what Sims et al. learned when they compared bird density and cat density: in many cases, there were more birds in the very areas where there were more cats—even species considered especially vulnerable to predation by cats. It may be, suggest Sims et al., that, because high cat density corresponds closely to high housing density, this measure is also an indication of those areas “where humans provide more supplementary food for birds.” [7]

Another explanation: “consistently high cat densities in our study areas… and thus uniformly high impacts of cat populations on urban avian assemblages.” [7] (Interestingly, the authors never consider that they might be observing uniformly low impacts.)

The bottom line? It’s difficult enough to show a direct link between observed predation and population impacts; suggesting a causal connection between high cat densities and declining bird populations is misleading and irresponsible. (Not that Dauphine and Cooper are the only ones to attempt it; recall that no predation data from Coleman and Temple’s “Wisconsin Study” were ever published, despite numerous news stories in which Temple referred to their existence in some detail [8–10].)

Predation Pressure
Dauphine and Cooper make a similar leap when, to buttress their claim that “TNR does not reduce predation pressure on native wildlife,” [1] they cite a study not about predation, but about the home ranges of 27 feral cats on Catalina Island.

While it’s true that the researchers found “no significant differences… in home-range areas or overlap between sterilized and intact cats,” [11] this has as much due to their tiny sample size as anything else. And the difference in range size between the four intact males and the four sterilized males was—while not statistically significant—revealing.

The range of intact males was 33–116 percent larger during the non-breeding season, and 68–80 percent larger during the breeding season. In his study of “house-bound” cats, Liberg, too, found differences: “breeding males had ranges of 350–380 hectares; ranges of subordinate, non-breeding males were around 80 hectares, or not much larger than those of females.” [12]

All of which suggests smaller ranges for males that are part of TNR programs. What any of this has to do with “predation pressure on native wildlife,” however, remains an open question.

On the other hand, Castillo and Clarke (whose paper Dauphine and Cooper cite) actually documented remarkably little predation among the TNR colonies they studied. In fact, over the course of approximately 300 hours of observation (this, in addition to “several months identifying, describing, and photographing each of the cats living in the colonies” [13] prior to beginning their research), Castillo and Clarke “saw cats kill a juvenile common yellowthroat and a blue jay. Cats also caught and ate green anoles, bark anoles, and brown anoles. In addition, we found the carcasses of a gray catbird and a juvenile opossum in the feeding area” [13].

Another of Dauphine and Cooper’s “facts”—that “TNR does not typically reduce feral cat populations”—is contradicted by another one of the studies they cite. Contrary to what the authors suggest, Felicia Nutter’s PhD thesis work showed that “colonies managed by trap-neuter-return were stable in composition and declining in size throughout the seven year follow-up period.” [14]

Indeed, Nutter observed a mean decrease of 36 percent (range: 30–89 percent) in the six TNR colonies they studied over two years. By contrast, the three control colonies increased in size an average of 47 percent. [15]

Additional TNR success stories Dauphine and Cooper fail to acknowledge:

Natoli et al. reported a 16–32 percent decrease in population size over a 10-year period across 103 colonies in Rome—despite a 21 percent rate of “cat immigration.” [16]

As of 2004, ORCAT, run by the Ocean Reef Community Association (in the Florida Keys), had reduced its “overall population from approximately 2,000 cats to 500 cats.” [17] According to the ORCAT Website, the population today is approximately 350, of which only about 250 are free-roaming.

Toxoplasma gondii
In recent years, Toxoplasma gondii has been linked to the illness and death of marine life, primarily sea otters [18], prompting investigation into the possible role of free-roaming (both owned and feral) cats. [19, 20] But if, as the authors claim, “the science points to cats,” then it does so rather obliquely, an acknowledgement Jessup and Miller make begrudgingly:

“Based on proximity and sheer numbers, outdoor pet and feral domestic cats may be the most important source of T. gondii oocysts in near-shore marine waters. Mountain lions and bobcats rarely dwell near the ocean or in areas of high human population density, where sea otter infections are more common.” [21, emphasis mine]

Correlation, however, is not the same as causation. And not all T. gondii is the same.

In a study of southern sea otters from coastal California, conducted between 1998 and 2004, a team of researches—including Jessup and Miller—found that 36 of 50 otters were infected with the Type X strain of T. gondii, one of at least four known strains. [22] Jessup and Miller were also among 14 co-authors of a 2008 paper (referenced in their contribution to “The Impact of Free Ranging Cats”) in which the Type X strain was linked not to domestic cats, but to wild felids:

“Three of the Type X-infected carnivores were wild felids (two mountain lions and a bobcat), but no domestic cats were Type X-positive. Examination of larger samples of wild and domestic felids will help clarify these initial findings. If Type X strains are detected more commonly from wild felids in subsequent studies, this could suggest that these animals are more important land-based sources of T. gondii for marine wildlife than are domestic cats.” [20, emphasis mine]

Combining the results of the two studies, then, nearly three-quarters of the sea otters examined as part of the 1998–2004 study were infected with a strain of T. gondii that hasn’t been traced to domestic cats. (I found this to be such surprising news that, months ago, I tried to contact Miller about it. Was I missing something? What studies were being conducted that might confirm or refute these finings? Etc. I never received a reply.)

As Miller et al. note, “subsequent studies” are in order. And it’s important to keep in mind their sample size was quite small: three bobcats, 26 mountain lions, and seven domestic cats (although the authors suggest at one point that only five domestic cats were included).

Still, a recently published study from Germany seems to support the hypothesis that the Type X strain isn’t found in domestic cats. Herrmann et al. analyzed 68 T. gondii-positive fecal samples (all from pet cats) and found no Type X strain. [23] (It’s interesting to note, too, that only 0.25 percent of the 18,259 samples tested positive for T. gondii.)

This is not to say that there’s no connection between domestic cats and Toxoplasmosis in sea otters, but that any “trickle-down effect,” as Jessup and Miller describe it, is not nearly as well understood as they imply. There’s too much we simply don’t know.

Money and Politics
I agree with Dauphine and Cooper that science is only part of the TNR debate—that it also involves “a complex mix of money, politics, intense emotions, and deeply divergent perspectives on animal welfare.” And I agree with their assessment of the progress being made by TNR supporters:

“Advocates of TNR have gained tremendous political strength in the U.S. in recent years. With millions of dollars in donor funding, they are influencing legislation and the policies of major animal-oriented nonprofit organizations.” [1]

What I find puzzling is Dauphine’s rather David-and-Goliath portrayal of the “cat lobby” (my term, not hers) they’re up against—in particular, her complaint, “promotion of TNR is big business, with such large amounts of money in play that conservation scientists opposing TNR can’t begin to compete.” [24]

The Cat Lobby
In “Follow the Money: The Economics of TNR Advocacy,” she notes that Best Friends Animal Society, “one of the largest organizations promoting TNR, took in over $40 million in revenue in 2009.” [24] Fair enough, but this needs to be weighed against expenses of $35.6 million—of which $15.5 million was spent on “animal care activities.”

But Dauphine’s got it wrong when she claims that Best Friends “spent more than $11 million on cat advocacy campaigns that year.” [24] Their financials—spelled out in the same document Dauphine cites—are unambiguous: $11.7 million in expenditures went to all “campaigns and other national outreach.” Indeed, there is no breakdown for “cat advocacy campaigns.”

Dauphine does a better job describing Alley Cat Allies’ 2010 financials: of the $5.2 million they took in, $3.3 million was spent in public outreach. But she’s overreaching in suggesting that their “Every Kitty, Every City” campaign is nationwide. For now, at least, it’s up and running in just “five major U.S. cities.”

Echoing Dauphine’s concerns, Florida attorney Pamela Jo Hatley decries ORCAT’s resources: “At a meeting hosted by the Ocean Reef Resort in June 2004,” recalls Hatley, “I learned that the ORCAT colony then had about 500 free-ranging cats, several paid employees, and an annual operating budget of some $100,000.” [25]

What Hatley fails to mention is how those resources have been used to make ORCAT a model for the rest of the country—using private donations. Hatley doesn’t seem to object to the U.S. Fish and Wildlife Service shelling out $50,000—of tax dollars—in 2007 to round up fewer than 20 cats (some of which were clearly not feral) along with 81 raccoons (53 of which were released alive) in the Florida Keys. [26, 27]

Following the Money
According to their 2008 Form 990, ORCAT took in about $278,000 in revenue, compared to $310,000 in expenses. How does that compare to some of the organizations opposing TNR? A quick visit to Guidestar.com helps put things in perspective.

In 2009, ABC took in just under $6 million, slightly more than their expenses.

TWS had $2.3 million in revenue in 2009, which was more than offset by expenses of $2.5 million.

Friends of the National Zoo, which oversees the Smithsonian Migratory Bird Center, showed $15 million in revenue, just exceeding their 2009 expenses of $14.7 million. (The Smithsonian Institute topped $1 billion in both the revenue and expense categories.)

And the National Audubon Society took in $61.6 million in 2008 (the most recent year for which information is available). And, despite expenses in excess of $86 million, finished the year with more than $255 million in net assets.

These numbers clearly don’t reflect the funding each organization dedicates to opposing TNR—but neither do they offer any evidence that, as Dauphine argues, “conservation scientists opposing TNR can’t begin to compete.”

Intense Emotions
Nobody familiar with the TNR debate would suggest that it’s not highly emotional. How can it be otherwise? Indeed, the very idea of decoupling our emotions from such important discourse is rather absurd.

Having an emotional investment in the debate does not, however, make one irrational or stupid.

“On the surface,” suggest Dauphine and Cooper, their tone unmistakably condescending, “TNR may sound reasonable, even logical.” [1] Gillin, for his part, bemoans the way the TNR debate “quickly shifts from statistics to politics to emotional arguments.” [2]

What’s particularly fascinating about all of this—the way TNR supporters are made out to be irrational (if not mentally ill—as in a letter to Conservation Biology last year, when several TNR opponents, including four contributors to “The Impact of Free Ranging Cats,” compared TNR to hoarding [28])—is just how emotionally charged the appeal of TNR opponents is.

Witness the “gruesome gallery of images,” for example, in which “one cat lies dead with a broken leg, one lies dying in a coat of maggots, and another suffers as ticks and ear mites plague its face.” [1] The idea, of course, is that these cats would have been better off if they’d been rounded up and killed “humanely.” A preemptive strike against the inevitability of “short, brutal lives.” (This phrase, which I first saw used by Jessup, [28] has become remarkably popular among TNR opponents.)

But is it that simple? Applying the same logic (if that’s what it is) to pelicans covered in oil, for instance, would we suggest that these birds should either be in captivity or “humanely euthanized”? Obviously not.

Divergent Perspectives on Animal Welfare
While I disagree that “the debate is predominately about whether cats should be allowed to run wild across the landscape and, if not, how to effectively and humanely manage them,” [29] I tend to agree with Lepczyk et al. when they write:

“It’s much more about human views and perceptions than science—a classic case where understanding the human dimensions of an issue is the key to mitigating the problem.” [29]

But, like Dauphine and Cooper, Lepczyk et al. seem more interested in broadcasting their message—loudly, ad nauseam—than in listening. “We need to understand whether people are even aware,” they write, “of the cumulative impact that their actions—choosing to let cats outdoors—can have on wildlife populations.” [29]

Although it’s packaged somewhat “softly,” we’re back to the same old speculative connections between predation and population impacts (familiar terrain for Lepczyk, who tried to connect these same dots in his PhD research). But how much of a connection is there, really? In their review of 61 predation studies, Mike Fitzgerald and Dennis Turner are unambiguous:

“We consider that we do not have enough information yet to attempt to estimate on average how many birds a cat kills each year. And there are few, if any studies apart from island ones that actually demonstrate that cats have reduced bird populations.” [30]

While the tone used by Lepczyk et al. is very much “we’re all in this together,” their prescription for “moving forward” suggests little common ground. (They actually cite that 2010 letter to Conservation Biology [28]—not much of an olive branch.)

“One approach is exemplified in Hawaii,” explain the authors, “where we’ve become part of a large coalition of stakeholders working together with the shared goal of reducing and eventually removing feral cats from the landscape.” [29] So, who’s involved?

“Our diverse group includes individuals from the Humane Society of the United States, the Hawaiian Humane Society, the U.S. Fish and Wildlife Service, the National Park Service, Hawaii’s Department of Land and Natural Resources, and the University of Hawaii. Our team also regularly interacts with other groups around the nation such as regional Audubon Societies and the American Bird Conservancy. Several stakeholders in the group have differing views, such as on whether or not euthanasia or culling is appropriate, or whether people should feed feral cats.” [29]

Other than the Humane Society organizations (whose position on TNR I don’t take for granted, considering they were early supporters of ABC’s Cats Indoors! campaign [31]), I don’t see a real diversity of views in this coalition.

I suppose it’s easy to make room at the table when you’re offering so few seats.

For Dauphine, though, any such collaboration approaches treason. Or selling out, at least.

“In some cases,” she explains, “conservation groups accept funding to join in efforts promoting TNR. The New Jersey Audubon Society, for example, had previously rejected TNR but began supporting it in 2005, acknowledging funding from the Frankenberg and Dodge Foundations for collaboration with TNR groups.” [24]

Dauphine doesn’t go into detail about the amount of funding, and it’s not clear what, if any, role it played in the decision by NJAS (which took in $6.8 million in 2008) to participate in the New Jersey Feral Cat-Wildlife Coalition—the kind of collaborative effort that should be encouraged, not derided:

“From 2002 to 2005, NJAS had actively opposed the practice of TNR in New Jersey. Despite this opposition, municipalities continued to adopt TNR ordinances. In 2005, NJAS, American Bird Conservancy, Neighborhood Cats and Burlington Feral Cat Initiative began exploratory dialogue about implementing standards to protect rare wildlife vulnerable to cat predation in towns which have already adopted TNR programs.” [32]

Message Received, Loud and Clear
Rather than wringing their hands over how to “better communicate the science” [1] or how to better facilitate “legal or policy changes, incentives, and increased education,” [29] TNR opponents might want to reconsider the message itself.

What they are proposing is the killing—on an unprecedented scale—of this country’s most popular pet.

I don’t imagine this tests well with focus groups and donors, of course, but there it is.

These people seem perplexed by a community’s willingness to adopt TNR (“In the end,” lament Lepczyk et al., referring to the decision in Athens, GA, “the professional opinion of wildlife biologists counted no more than that of any other citizen, a major reason for the defeat.” [29]) but fail to recognize how profoundly unpalatable their alternative is.

And, unworkable, too.

Which may explain why it’s virtually impossible to get them to discuss their “plan” in any detail. (I was unsuccessful, for example, in pinning down Travis Longcore during our back-and-forth on the Audubon magazine’s blog and couldn’t get Jessup or Hutchins to bite when I asked the same question during an online discussion of public health risks.)

In light of what’s involved with “successful” eradication programs, I’m not surprised by their eagerness to change the subject.

On Marion Island, it took 19 years to eradicate something like 2,200 cats—using disease (feline distemper), poisoning, intensive hunting and trapping, and dogs. This on an island that’s only 115 square miles in total area, barren, and uninhabited. [33, 34] The cost, I’m sure, was astronomical.

On the sparsely populated (fewer than 1,000, according to Wikipedia) Ascension Island (less than 34 total square miles), a 2003 eradication effort cost nearly $950,000 (adjusted to 2009 dollars). [35]

A 2000 effort on Tuhua (essentially uninhabited, and just 4.9 square miles) ran $78,591 (again, adjusted to 2009 dollars). [35]

Efforts on Macquarie Island (also small—47.3 square miles—and essentially uninhabited) proved particularly costly: $2.7 million in U.S. (2009) dollars. And still counting. The resulting rebound in rabbit and rodent numbers prompted “Federal and State governments in Australia [to commit] AU$24 million for an integrated rabbit, rat and mouse eradication programme.” [36] (To put this into context, Macquarie Island is about one-third the size of the Florida Keys.)

These examples represent, in many ways, low-hanging fruit. By contrast, “the presence of non-target species and the need to safely mitigate for possible harmful effects, along with substantial environmental compliance requirements raised the cost of the eradication.” [37] Eradicating rodents from Anacapa Island, “a small [1.2-square-mile] island just 80 miles from Los Angeles International Airport, cost about $2 million.” [38]

Now—setting aside the horrors involved—how exactly do TNR opponents propose to rid the U.S. of it’s millions of feral cats? [cue the sound track of crickets chirping]

I think the general public is starting to catch on. Even if they fall for the outlandish claims about predation, wildlife impacts, and all the rest—they don’t see anything in the way of a real solution. As Mark Kumpf, former president of the National Animal Control Association, put it in an interview with Animal Sheltering magazine, “the traditional methods that many communities use… are not necessarily the ones that communities are looking for today.” [39]

“Traditional” approaches to feral cat management (i.e., trap-and-kill) are, says Kumpf, akin to “bailing the ocean with a thimble.” [39]

For all their apparent interest—22 pages in the current issue of The Wildlife Professional alone—TWS might as well be handing out thimbles to its members. Although Gillin’s “Leadership Letter” invites “dialogue among all stakeholders,” it offers nothing substantive to advance the discussion:

“If removal and euthanasia of unadoptable feral cats is not acceptable to TNR proponents, then they need to offer the conservation community a logical, science-based proposal that will solve the problem of this invasive species and its effect on wildlife and the environment.” [2]

So much for leadership.

Literature Cited
1. Dauphine, N. and Cooper, R.J., “Pick One: Outdoor Cats or Conservation.” The Wildlife Professional. 2011. 5(1): p. 50–56.

2. Gillin, C., “The Cat Conundrum.” The Wildlife Professional. 2011. 5(1): p. 10, 12.

3. APPA, 2009–2010 APPA National Pet Owners Survey. 2009, American Pet Products Association: Greenwich, CT. http://www.americanpetproducts.org/pubs_survey.asp

4. Lord, L.K., “Attitudes toward and perceptions of free-roaming cats among individuals living in Ohio.” Journal of the American Veterinary Medical Association. 2008. 232(8): p. 1159-1167. http://www.avma.org/avmacollections/feral_cats/javma_232_8_1159.pdf

6. van Heezik, Y., “A New Zealand Perspective.” The Wildlife Professional. 2011. 5(1): p. 70.

7. Sims, V., et al., “Avian assemblage structure and domestic cat densities in urban environments.” Diversity and Distributions. 2008. 14(2): p. 387–399. http://dx.doi.org/10.1111/j.1472-4642.2007.00444.x

8. Wilson, M. (1997). Cats Roaming Free Take a Toll on Songbirds. Boston Globe, p. 11.

9. Seppa, N. (1993, July 22). Millions of Songbirds, Rabbits Disappearing. Wisconsin State Journal, p. 1A.

10. Wozniak, M.D. (1993, August 3). Feline felons: Barn cats are just murder on songbirds. The Milwaukee Journal, p. A1.

11. Guttilla, D.A. and Stapp, P., “Effects of sterilization on movements of feral cats at a wildland-urban interface.”Journal of Mammalogy. 2010. 91(2): p. 482–489. http://dx.doi.org/10.1644/09-MAMM-A-111.1

12. Liberg, O. and Sandell, M., Spatial organisation and reproductive tactics in the domestic cat and other felids, in The Domestic cat: The biology of its behaviour, D.C. Turner and P.P.G. Bateson, Editors. 1988, Cambridge University Press: Cambridge; New York. p. 83–98.

13. Castillo, D. and Clarke, A.L., “Trap/Neuter/Release Methods Ineffective in Controlling Domestic Cat “Colonies” on Public Lands.” Natural Areas Journal. 2003. 23: p. 247–253.

14. Nutter, F.B., Evaluation of a Trap-Neuter-Return Management Program for Feral Cat Colonies: Population Dynamics, Home Ranges, and Potentially Zoonotic Diseases, in Comparative Biomedical Department. 2005, North Carolina State University: Raleigh, NC. p. 224.

15. Stoskopf, M.K. and Nutter, F.B., “Analyzing approaches to feral cat management—one size does not fit all.”Journal of the American Veterinary Medical Association. 2004. 225(9): p. 1361–1364. http://www.ncbi.nlm.nih.gov/pubmed/15552309

www.avma.org/avmacollections/feral_cats/javma_225_9_1361.pdf

16. Natoli, E., et al., “Management of feral domestic cats in the urban environment of Rome (Italy).” Preventive Veterinary Medicine. 2006. 77(3-4): p. 180-185. http://www.sciencedirect.com/science/article/B6TBK-4M33VSW-1/2/0abfc80f245ab50e602f93060f88e6f9

www.kiccc.org.au/pics/FeralCatsRome2006.pdf

17. Levy, J.K. and Crawford, P.C., “Humane strategies for controlling feral cat populations.” Journal of the American Veterinary Medical Association. 2004. 225(9): p. 1354–1360. http://www.avma.org/avmacollections/feral_cats/default.asp

http://www.avma.org/avmacollections/feral_cats/javma_225_9_1354.pdf

18. Jones, J.L. and Dubey, J.P., “Waterborne toxoplasmosis – Recent developments.” Experimental Parasitology. 124(1): p. 10-25. http://www.sciencedirect.com/science/article/B6WFH-4VXB8YT-2/2/8f9562f64497fe1a30513ba3f000c8dc

19. Dabritz, H.A., et al., “Outdoor fecal deposition by free-roaming cats and attitudes of cat owners and nonowners toward stray pets, wildlife, and water pollution.” Journal of the American Veterinary Medical Association. 2006. 229(1): p. 74-81. http://www.avma.org/avmacollections/feral_cats/javma_229_1_74.pdf

20. Miller, M.A., et al., “Type X Toxoplasma gondii in a wild mussel and terrestrial carnivores from coastal California: New linkages between terrestrial mammals, runoff and toxoplasmosis of sea otters.” International Journal for Parasitology. 2008. 38(11): p. 1319-1328. http://www.sciencedirect.com/science/article/B6T7F-4RXJYTT-2/2/32d387fa3048882d7bd91083e7566117

21. Jessup, D.A. and Miller, M.A., “The Trickle-Down Effect.” The Wildlife Professional. 2011. 5(1): p. 62–64.

22. Conrad, P.A., et al., “Transmission of Toxoplasma: Clues from the study of sea otters as sentinels of Toxoplasma gondii flow into the marine environment.” International Journal for Parasitology. 2005. 35(11-12): p. 1155-1168. http://www.sciencedirect.com/science/article/B6T7F-4GWC8KV-2/2/2845abdbb0fd82c37b952f18ce9d0a5f

23. Herrmann, D.C., et al., “Atypical Toxoplasma gondii genotypes identified in oocysts shed by cats in Germany.”International Journal for Parasitology. 2010. 40(3): p. 285–292. http://www.sciencedirect.com/science/article/B6T7F-4X1J771-2/2/dc32f5bba34a6cce28041d144acf1e7c

24. Dauphine, N., “Follow the Money: The Economics of TNR Advocacy.” The Wildlife Professional. 2011. 5(1): p. 54.

25. Hatley, P.J., “Incompatible Neighbors in the Florida Keys.” The Wildlife Professional. 2011. 5(1): p. 52–53.

26. O’Hara, T. (2007, April 3). Fish & Wildlife Service to begin removing cats from Keys refuges. The Key West Citizen, from http://keysnews.com/archives

27. n.a., Lower Florida Keys National Wildlife Refuges Comprehensive Conservation Plan. 2009, U.S. Department of the Interior, Fish and Wildlife Service: Atlanta, GA. http://www.fws.gov/nationalkeydeer/

http://www.fws.gov/southeast/planning/PDFdocuments/Florida%20Keys%20FINAL/TheKeysFinalCCPFormatted.pdf

28. Jessup, D.A., “The welfare of feral cats and wildlife.” Journal of the American Veterinary Medical Association. 2004. 225(9): p. 1377-1383. http://www.ncbi.nlm.nih.gov/pubmed/15552312

http://www.avma.org/avmacollections/feral_cats/javma_225_9_1377.pdf

29. Lepczyk, C.A., van Heezik, Y., and Cooper, R.J., “An Issue with All-Too-Human Dimensions.” The Wildlife Professional. 2011. 5(1): p. 68–70.

30. Fitzgerald, B.M. and Turner, D.C., Hunting Behaviour of domestic cats and their impact on prey populations, in The Domestic Cat: The biology of its behaviour, D.C. Turner and P.P.G. Bateson, Editors. 2000, Cambridge University Press: Cambridge, U.K.; New York. p. 151–175.

31. Berkeley, E.P., TNR Past present and future: A history of the trap-neuter-return movement. 2004, Bethesda, MD: Alley Cat Allies.

32. Stiles, E., NJAS Works with Coalition to Reduce Bird Mortality from Outdoor Cats. 2008, New Jersey Audubon Society. http://www.njaudubon.org/Portals/10/Conservation/PDF/ConsReportSpring08.pdf

33. Bester, M.N., et al., “A review of the successful eradication of feral cats from sub-Antarctic Marion Island, Southern Indian Ocean.” South African Journal of Wildlife Research. 2002. 32(1): p. 65–73.

http://www.ceru.up.ac.za/downloads/A_review_successful_eradication_feralcats.pdf

34. Bloomer, J.P. and Bester, M.N., “Control of feral cats on sub-Antarctic Marion Island, Indian Ocean.” Biological Conservation. 1992. 60(3): p. 211-219. http://www.sciencedirect.com/science/article/B6V5X-48XKBM6-T0/2/06492dd3a022e4a4f9e437a943dd1d8b

35. Martins, T.L.F., et al., “Costing eradications of alien mammals from islands.” Animal Conservation. 2006. 9(4): p. 439–444. http://onlinelibrary.wiley.com/doi/10.1111/j.1469-1795.2006.00058.x/abstract

http://i3n.iabin.net/documents/pdf/Costingeradicationsofalienmammalsfromislands.pdf

36. Bergstrom, D.M., et al., “Indirect effects of invasive species removal devastate World Heritage Island.” Journal of Applied Ecology. 2009. 46(1): p. 73-81. http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2664.2008.01601.x/abstract

http://eprints.utas.edu.au/8384/4/JAppEcol_Bergstrom_etal_journal.pdf

37. Donlan, C.J. and Heneman, B., Maximizing Return on Investments for Island Restoration with a Focus on Seabird Conservation. 2007, Advanced Conservation Strategies: Santa Cruz, CA. http://www.advancedconservation.org/roi/ACS_Seabird_ROI_Report.pdf

38. Donlan, C.J. and Wilcox, C., Complexities of costing eradications, in Animal Conservation. 2007, Wiley-Blackwell. p. 154–156. http://onlinelibrary.wiley.com/doi/10.1111/j.1469-1795.2007.00101.x/abstract

http://www.advancedconservation.org/library/donlan_&_wilcox_2007a.pdf

39. Hettinger, J., Taking a Broader View of Cats in the Community, in Animal Sheltering. 2008. p. 8–9. http://www.animalsheltering.org/resource_library/magazine_articles/sep_oct_2008/taking_a_broader_view_of_cats.html

http://www.animalsheltering.org/resource_library/magazine_articles/sep_oct_2008/broader_view_of_cats.pdf

Keys: To the Future

3 Feb 2011•In the News, Policy Issues, Vox Felina

Below is a slightly reformatted version of the comments I submitted in response to the Florida Keys National Wildlife Refuges Complex Integrated Predator Management Plan/Draft Environmental Assessment. A PDF version is available here.

• • •

To Whom It May Concern:

I am writing to comment on the Florida Keys National Wildlife Refuges Complex Integrated Predator Management Plan/Draft Environmental Assessment. As I point out below, the IPMP/EA proposed by FWS fails to adequately address—or overlooks entirely—several key issues. Only now, for example—after years of struggling with this issue—does FWS propose to “implement monitoring and conduct further research as needed to determine abundance and distribution of free-roaming cats throughout the Refuge, document effectiveness of management actions taken or not taken on cat populations, and determine the impacts on the ecosystems and native species to aid in the adaptive management process.” [1]

How can FWS even put forward its IPMP/EA without this critical information in hand? One would expect, under the circumstances, that population estimates and scat analysis, for instance—along with whatever additional research might better inform any proposed action by FWS—would form the basis of such an IPMP/EA.

In addition, the IPMP/EA fails to address risks inherent with the improper management of free-roaming cats in the Keys. The plan proposed by FWS is unlikely to result in the removal of cats at a rate sufficient to keep pace with reproduction—a situation exacerbated greatly by its insistence on banning the feeding of feral cats and Trap-Neuter-Return (TNR) programs. Consequently, the population of feral cats may very well increase. And even if FWS is successful at removing cats from some locations, the IPMP/EA fails to take into account the risk of mesopredator release—the inevitable spike in non-native rodent populations—and its impact on the native species the IPMP/EA aims to protect.

For these reasons (each of which is outlined in detail below), I strongly encourage FWS to revise its IPMP/EA, especially as it pertains to the removal of feral cats.

Justification for Action
After a thorough reading of the Draft Environmental Assessment (EA) for the Florida Keys National Wildlife Refuges Complex (FKNWRC) Integrated Predator Management Plan—along with several supporting documents (as described below)—I am struck by how inadequately the IPMP/EA addresses several critical issues. Indeed, the Plan’s Justification for Management Action suggests that FWS has an insufficient and/or largely incorrect understanding of the impacts of feral and free-roaming cats on native wildlife and the environment.

Extinctions
Among the studies FWS cites to support its claim that “free-roaming cats have been shown to be a major cause of 33 native species extinction globally,” [1] is a 1987 paper by Cruz and Cruz, in which the authors, studying Galápagos Petrels, found that cats were hardly the only culprits:

“They are threatened by introduced rats, which attack eggs and young chicks… dogs and pigs which prey on eggs, nestlings and adults. Introduced goats, burros and cattle destroy nesting habitat and trample nests. A different combination of these pests and predators exists at each of the petrel nesting sites, while three of the islands are plagued by all of them.” [2]

The FWS would have the public believe the Galápagos Petrel is among those 33 extinctions. In fact, the birds are still there, though they are listed as Critically Endangered.

The story is similar for the 1986 paper by Kirkpatrick and Rauzon, another purported link between free-roaming cats and species extinctions. In fact, Kirkpatrick and Rauzon found that more than 90 percent of the diet of free-roaming cats on Jarvis Island and Howland Island was made up of Sooty Terns, Wedge-tailed Shearwaters, and Brown Noddies—each of which is listed as a species of Least Concern. [3]

Another of the papers cited by FWS has nothing to do with extinctions at all. As the authors describe it, their study was an evaluation of “whether a collar-worn pounce protector, the CatBib, reduces the number of vertebrates caught by pet cats and whether its effectiveness was influenced by colour or adding a bell.” [4]

Also listed among the “evidence” of island extinctions were studies that—in addition to having nothing to do with extinctions—were not conducted on islands. Coleman and Temple’s 1993 survey, for example, involved rural Wisconsin residents and their outdoor cats, [5] while Churcher and Lawton surveyed residents of a small English village. [6]

Threatened or Endangered Species
FWS’s assertion that “many of the species impacted by free-roaming cats are federally listed threatened or endangered species and federally protected migratory birds” [1] is, while probably true, also largely meaningless. According to the 2009 State of the Birds report, published by the Department of the Interior:

“The United States is home to a tremendous diversity of native birds, with more than 800 species inhabiting terrestrial, coastal, and ocean habitats, including Hawaii. Among these species, 67 are federally listed as endangered or threatened. An additional 184 are species of conservation concern because of their small distribution, high threats, or declining populations.” [7]

That translates to approximately 31 percent of all birds in this country being species of concern. FWS makes it sound as if perhaps the cats are targeting these birds; in fact, it’s obvious that all forms of mortality pose an acute threat to these vulnerable populations.

Disruptions to Native Ecosystems
When it comes to the disruption caused by cats to “the abundance, diversity, and integrity of native ecosystems,” FWS turns to, among others, studies by Hawkins [8] and Jessup. [9]

But Hawkins’ dissertation work is plagued with problems that raise serious doubts about his rather triumphant conclusions—“the preference of ground feeding birds for the no-cat treatment was striking,” [8] for example. A closer look reveals that five of the nine ground-feeding birds in his study showed no preference for either area of the study site (a fact Hawkins downplays considerably). Without any explanation for why these vulnerable bird species were indifferent to the presence of an opportunistic predator, Hawkins is in no position to make the causal connections he does.

Jessup cites some well-known predation studies, but his concern is not the (presumed) impact on wildlife, per se, but rather the wholesale condemnation of “trap, neuter, and reabandon,” [9] as he calls it.

Birds and Cats
FWS claims that “free-roaming cats kill at least one billion birds every year in the U.S., representing one of the largest single sources of human-influenced mortality for small native wildlife,” [1] supporting the assertion with just three sources, one of which is Rich Stallcup’s 1991 article from the Observer, a publication of the Point Reyes Bird Observatory. But “A Reversible Catastrophe” is very light on science—and, frankly, Stallcup gets most of that wrong. Mainly, the article is Stallcup’s manifesto regarding neighborhood cats:

“If you have a garden, why not proclaim it a wildlife sanctuary and protect it from non-native predators? If roaming cats come into your sanctuary to poach the wildlife under your stewardship, you have the right and perhaps even the duty to discourage them in a serious way.” [10]

Stallcup goes on to suggest that gardeners “…try a B-B or pellet gun. There is no need to kill or shoot toward the head, but a good sting on the rump seems memorable for most felines, and they seldom return for a third experience.” [10]

Another of the studies cited by FWS—a 2008 paper by Sax and Gaines—isn’t about cats at all. Or even invasive animals. Although the authors do mention “the extinction of many native animal species on islands” [11] briefly in their introduction, the purpose of the paper is, as the authors state plainly enough, to “show that the number of naturalized plant species has increased linearly over time on many individual islands.” [11, emphasis mine]

Nevertheless, the assertion—made by FWS and many others, too—that “cats kill at least one billion birds every year in the U.S.” deserves careful scrutiny. Such aggregate figures can typically be traced to small—often flawed—studies, the results of which are subsequently extrapolated from one habitat to another, conflating island populations with those on continents, combining common and rare bird species, and so forth. Perhaps the most famous example of such pseudoscientific manipulation is the infamous “Wisconsin Study” by Coleman and Temple.

Actually, there was no Wisconsin Study, in the scientific, peer-reviewed-publication sense. The often-cited “estimates”—which have, over the past 15 years, taken on mythical status—were nothing more than back-of-the envelopes guesses. Indeed, co-author Stanley Temple himself admitted that their figures weren’t “actual data,” though many—including the FWS—continue treating these figures as if they were actual data. “That was just our projection to show how bad it might be,” noted Temple. [12]

But Temple wasn’t as forthright about was the origin of their “estimates.” The authors’ “intermediate” figure of “38.7 million birds killed by rural cats” [13] is based on the results of a study involving just four “urban” cats and one rural cat in Virginia [14, 15] (this, in addition to Coleman and Temple’s several flawed assumptions). And their high estimate was even less valid.

Something else often left out of the debate: predation—even at high levels—does not automatically lead to population declines. In fact, some studies [16, 17] have shown that birds killed by cats are, on average, significantly less healthy than those killed through non-predatory events (e.g., collisions with buildings).

In the end, enormous “estimates” of annual predation rates are utterly meaningless—useful only as a sensational talking point by organizations interested in vilifying free-roaming cats. Such figures are routinely “sold” to a mainstream media and public unfamiliar with the larger context.

Threats to Public Health
Citing the Centers for Disease Control website, FWS argues:

“…free-roaming cats not only threaten wildlife through direct predation but also serve as vectors for a number of diseases including rabies, cat scratch fever, hookworms, roundworms and toxoplasmosis. Some of these diseases can be transmitted to other domestic animals, native wildlife, and in some cases, humans.” [1]

In fact, the CDC site makes no mention of cats being a threat to wildlife. And humans? “Although cats can carry diseases and pass them to people, you are not likely to get sick from touching or owning a cat.” And, notes the CDC, “People are probably more likely to get toxoplasmosis from gardening or eating raw meat than from having a pet cat.”

There’s even a link to another page on the CDC’s site, called “Health Benefits of Pets.”

False Premises
The numerous misrepresentations, oversights, and errors outlined above suggest quite clearly that FWS either lacks a sufficient grasp of the critical issues involved—or that it’s not interested in being forthright with the public. This is not an academic issue; nor should my detailed criticism be considered nitpicking. After all, it’s quite clear that FWS intends to eliminate free-roaming cats on public—and, if possible, also private—land throughout the Keys. As “justification for action,” the IPMP/EA falls well short of what is required; as a public record, it is wholly unacceptable—and, to be very candid about it—an embarrassment to the agency and the people involved. Simply put, any subsequent action taken by FWS on the basis of this IPMP/EA can, I think, rightfully be considered unjustified.

Moreover, in its attempt to focus on the impacts of cats, FWS overlooks some key factors. As a result, implementation of the IPMP/EA may very well increase the threat to the Keys’ native wildlife.

Mesopredator Release
In its IPMP/EA, FWS refers to two often-cited papers [18, 19] as evidence of cats disrupting native ecosystems, but fails to acknowledge the larger point made by the authors: the mesopredator release phenomenon. “In the absence of large, dominant predators,” write Soulé et al., “smaller omnivores and predators undergo population explosions, sometimes becoming four to 10 times more abundant than normal.” [18]

For Soulé et al., coyotes were the dominant predators, while cats were the mesopredators. In other contexts, however, cats have been shown to play the dominant predator role with non-native rats becoming the mesopredators. [20–23].

Mathematical modeling of the mesopredator release phenomenon illustrates the complexities involved in eradication efforts, even on small islands. As Courchamp et al. explain, “although counter-intuitive, eradication of introduced superpredators, such as feral domestic cats, is not always the best solution to protect endemic prey when introduced mesopredators, such as rats, are also present.” [22] Fan et al. warn of the risks involved with such eradication efforts: “In some cases, it may cause a disastrous impact to managed or natural ecosystems.” [21]

Macquarie Island, located roughly halfway between New Zealand and Antarctica, offers a well-documented example of such a disastrous impact. In 2000, cats were eradicated from this United Nations Educational, Scientific and Cultural Organization World Heritage Site in order to protect its seabird populations. The resulting rebound in rabbit and rodent numbers, however, has had its own disastrous impact. “In response, Federal and State governments in Australia have committed AU$24 million for an integrated rabbit, rat and mouse eradication programme.” [23]

Mesopredator Release in the Keys
But FWS doesn’t even mention the risk of mesopredator release in its IPMP/EA, despite the fact that—should the population of free-roaming cats be sufficiently reduced—the situation in the Keys suggests that such an outcome is actually quite likely. (Because the population and diet of these cats is poorly understood in the Keys, the degree of reduction that would trigger a mesopredator release, too, is unknown.)

According to FWS, non-native rats are already “prevalent in residential and commercial areas.” [1] Should the removal of cats create a spike in their numbers, FWS suggests that they’re prepared to remove the rats, too: “Noticeable population increases based on reports, road kill, or other specific or auxiliary data may initiate targeted control and eradication efforts in addition to incidental capture…” [1]

But controlling these rats is complicated considerably by the need to protect Lower Keys marsh rabbits. The South Florida Multi-Species Recovery Plan (MSRP) warns of these rabbits coming into contact with pesticides and “poisons used to control black rats.” [24]

“In a 1993 Biological Opinion, the FWS investigated the effects of vertebrate control agents on endangered and threatened species and determined that several chemicals (e.g., Pival) would jeopardize the continued existence of the Lower Keys marsh rabbit. Chemicals—such as Pival—a rodenticide used to kill rats, are lethal if ingested. The FWS also concluded that if development in the Keys continues to increase, the potential for these animals to come in contact with such chemicals also increases, as does the potential for their extinction. Based on these findings, the FWS believes the continued use of such chemicals will result in the deaths of Lower Keys marsh rabbits. Given that the majority of occupied habitat is adjacent to urbanized areas, and that urbanization continues to expand into their habitat, then it can reasonably be predicted that the use of such chemicals has had a negative impact upon the Lower Keys marsh rabbit that may prevent its recovery.” [24]

Again, there’s no consideration whatsoever in the IPMP/EA for how the Lower Keys marsh rabbits—the protection of which was a key factor in the creation of the IPMP/EA in the first place—will be protected from increased predatory pressure by non-native rats. Yet, based on the evidence presented by FWS, it’s quite clear that the elimination of free-roaming cats in the Keys will very likely have a negative impact on their numbers—and may very well lead to the extirpation of marsh rabbits from any Key where these rats are present.

The same may be true of the Key Largo cotton mouse [25, 26], Key Largo woodrat [27, 28], and silver rice rat [29, 30], all of which are identified as species of particular concern in the IPMP/EA, and which are threatened—either through predation or competition—by non-native rats such as the black rat.

Alternatives
According to FWS, “the Proposed Action is a fully integrated range of nonlethal and lethal predator management strategies that would be available for implementation on the FKNWRC, depending on the status, distribution, and extent of predation by targeted predator species.” [1] Where feral cats are concerned, however, the “Proposed Action” is nothing more than the “traditional” trap-and-kill approach—this, despite the fact that FWS lacks sufficient data concerning the distribution of, and extent of predation by, feral cats.

FWS is less than forthright on this point, however. According to the IPMP/EA:

“The Monroe County animal control service provider will have the authority to determine the final disposition of the trapped cats according to county ordinances and standards, which may include returning to owner, adopting out, relocating to a long-term cat care facility on the mainland, or euthanizing.” [1]

It’s no secret what happens to nearly every feral cat brought into shelters. As Nathan Winograd writes in his book Redemption: The Myth of Pet Overpopulation and the No Kill Revolution in America, “there is no other animal entering a shelter whose prospects are so grim and outcome so certain.” [31]

I asked Connie Christian, Executive Director of the Florida Keys SPCA about this last month. “Every cat brought to our facility is assessed to determine their disposition,” Christian told me via e-mail. “Every attempt is made to return ‘non-feral’ cats to their owners or place for adoption.”

(As I understand it, there was a no-kill shelter available at the time of the stakeholder meetings, thus buy-in from those concerned for the welfare of these cats. However, as this is no longer the case (again, this is my understanding of the situation), FWS cannot assume that the same level of buy-in exists today. And in any case, the suggestion of a no-kill shelter or sanctuary as a solution to the Keys’ feral cat issue is at best disingenuous.)

Removing Cats
Setting aside for the moment the issues mentioned above, the IPMP/EA offers little to suggest that FWS will actually be able to remove the free-roaming cats from the Keys. The fact that the agency has no idea how many cats there are is only the beginning. Reports indicate that FWS has a rather poor track record when it comes to trapping cats. Its 2003 contract with USDA, for example, yielded just 23 cats over 31 days of trapping. [32]

In 2007, FWS “received $50,000 to remove cats from federal refuges on Big Pine Key and Key Largo, and to protect endangered marsh rabbits, silver rice rats and other animals and birds that call the refuges home.” [33] Unofficial reports (I’m told nothing official has been issued yet) suggest that fewer than 20 cats were caught—some of which were clearly not feral—along with 81 raccoons, 53 of which were released alive. [34]

I think it’s safe to say that the Keys’ wildlife reaped little or no benefit from either effort. Had the 2007 funding been used for TNR, on the other hand, the impact could have been substantial.

Eradication Efforts
As I’m sure FWS is aware, numerous eradication efforts—the horrors of which are spelled out in some of the papers cited in the IPMP/EA—have been used to successfully remove cats from islands:

Nogales et al., describing the “success” of Marion Island, note, “it took about 15 years of intense effort to eradicate the cats, combining several methods such as trapping, hunting, poisoning, and disease introduction… The use of disease agents or targeted poisoning campaigns hold promise for an initial population reduction in eradication programs on large islands—such an approach may save effort, time, and money.” [35]

Cruz and Cruz point out that, of all the non-native mammals there, cats were “the most difficult to control or eliminate on Floreana Island.” Although “hunting with dogs was the single most effective method employed and it gave a sure body count,” the authors warn that “the method was costly and with the limited manpower available was only useful over small areas. Both poisoning and trapping were effective and the combination of the three methods is probably the most effective approach, as well as being the best use of time and materials.” [2]

Veitch describes efforts on 11-square-mile Little Barrier Island as “a determined [cat] eradication attempt” involving “cage traps, leg-hold traps, dogs and 1080 poison were used, but leg-hold traps and 1080 poison were the only effective methods.” [35] Four cats were also infected with Feline enteritis, but “because of the poor reaction to the virus no other cats were dosed and none were released… Altogether, 151 cats were known to have been killed before the eradication was declared complete. Important lessons learnt can be transferred to other feral cat eradication programmes.” [36] (By way of comparison, the Keys are approximately 137 square miles in total area.)

As FWS notes in its IPMP/EA, such methods are “not… socially acceptable” and “inconsistent with the points of consensus developed by the stakeholder group.” While I agree completely that these methods are unacceptable, the “fully integrated range of nonlethal and lethal predator management strategies” proposed by FWS strike me as nothing more than business as usual. How will this be any different (other than perhaps in terms of scale) than the failed efforts of the past?

If implemented as-planned, it seems clear that FWS will not be able to remove the cats quickly enough to keep up with reproduction rates. Using a population model, Andersen, Martin, and Roemer have suggested that, in the absence of a sterilization program, 50 percent of cats would have to be removed in order for a colony to decrease 10 percent annually. [37] This model has its flaws (some of which are described in “Reassessment”) but even if Andersen et al. are off by a factor of two, FWS would need to remove 25 percent of the free-roaming, unsterilized (and in the absence of TNR, it won’t be long before that’s the norm) cats continuously in order to achieve a modest 10 percent annual reduction in overall numbers.

Does anybody at FWS really think that’s going to happen? Where’s the evidence to suggest that it’s even possible?

If the feeding of feral cats and TNR are eliminated (to whatever extent possible) throughout the Keys, these cats will simply “go underground.” That means no more monitoring—and sterilizing—by the “foot soldiers” who currently care for them.

Indeed, it’s quite likely that feral cat complaint calls to Monroe County, FWS, and USDA would taper off considerably, as it becomes clear that such a call is essentially a death sentence. Thus, the cats would become that much more difficult to locate—and sterilize. The population, therefore, would increase—probably very quickly.

In other words, the most likely outcome of the IPMP/EA put forward by FWS is an increase in the number of feral cats in the Keys—and, of course, a corresponding increase in the negative impacts they have on the area’s wildlife and environment.

Trap-Neuter-Return
In contrast to the IPMP/EA—with its risk of mesopredator release, on the one hand, and potential to inadvertently drive up the numbers of feral cats, on the other—TNR offers the potential to more carefully manage the population of feral cats in the Keys. Indeed, given the precarious nature of wildlife in the Keys, TNR may actually be the best approach to fulfill the purpose of the IPMP/EA:

“…conserve and restore federally-listed species and protect all native fauna and flora on the [refuges] from population decline and potential extirpation or extinction due to predation by non-native species and human-subsidized populations of native predators.” [1]

The fact that TNR was “considered but dismissed from further evaluation,” again, suggests that FWS failed to adequately analyze all of the available predator management alternatives. And, similar to its “justification for action,” FWS’s rationale for dismissing TNR doesn’t hold up to scrutiny.

FWS argues, for example, that TNR “does little to reduce cat predation on native wildlife.” Although few predation studies have examined the hunting behavior of cats belonging to managed colonies, those that have are revealing. Reporting on their study of free-roaming cats in Brooklyn, Calhoon and Haspel write: “Although birds and small rodents are plentiful in the study area, only once in more than 180 [hours] of observations did we observe predation.” [38]

And Castillo and Clarke (though highly critical of TNR) actually documented remarkably little predation in the two Florida parks they used for their study. In fact, over the course of approximately 300 hours of observation (this, in addition to “several months identifying, describing, and photographing each of the cats living in the colonies” [39] prior to beginning their research), Castillo and Clarke “saw cats kill a juvenile common yellowthroat and a blue jay. Cats also caught and ate green anoles, bark anoles, and brown anoles. In addition, we found the carcasses of a gray catbird and a juvenile opossum in the feeding area.” [39]

“In addition,” argues FWS, “the TNR method has little valid scientific support for claims that it actually reduces cat colony numbers over time and often has been shown to attract people to release new cats into an area.” [1] Ironically, some of the greatest TNR success stories are right there in the papers cited by FWS. Natoli, for example, reported a 16–32 percent decrease in population size over a 10-year period across 103 colonies in Rome—despite a 21 percent rate of “cat immigration.” [40] And, as of 2004, ORCAT, run by the Ocean Reef Community Association, had reduced its “overall population from approximately 2,000 cats to 500 cats.” [41] According to the ORCAT website, the population today is approximately 350, of which only about 250 are free-roaming.

Any TNR program contends with the unfortunate (and illegal) dumping of cats. Still, it’s difficult to imagine that the presence or absence of a nearby TNR program would affect a person’s decision to abandon his/her pet cat(s). (If any studies had demonstrated such a connection, TNR opponents would surely cite them.) On the other hand, cats dumped near a managed colony are far more likely to be adopted and/or sterilized—thereby mitigating their potential impact on the overall population of unowned cats—as well any impacts to wildlife and the environment.

Moreover, FWS ignores the value of population stabilization. Julie Levy, Maddie’s Professor of Shelter Medicine in the University of Florida’s College of Veterinary Medicine, and one of the country’s foremost experts on feral cats, argues that “wildlife benefits when populations of cats that are trending rapidly upwards are at least stabilized.” [42] Nothing in the IPMP/EA suggests that such stabilization will be achieved in the Keys.

ESA and MBTA
Among the more perplexing aspects of FWS’s argument is their claim that “TNR practices are prohibited on National Wildlife Refuges, and violate the Endangered Species Act (ESA) and the Migratory Bird Treaty Act (MBTA) because they may result in the direct harm of protected species.”

This is an argument that’s been thrown around since at least 2003, when Pamela Jo Hatley, then a law student, suggested the possibility. But that’s all it was—and, apparently, is—a possibility.

“It is quite obvious that cats can be lethal to birds,” writes Hatley, “and if the death of a migratory bird can be traced to a cat, or a cat colony, which can be further traced to an individual or organization, there may be strict liability for that person under the MBTA.” [43] Hatley’s argument for violations of the Endangered Species Act is similarly speculative: “…persons who release cats into the wild or who maintain feral cat colonies could be found liable for a take under section 9 of the ESA if maintenance of feral cats in the wild is found to kill or injure wildlife by degrading habitat.” [43]

It’s been nearly eight years now—a period during which TNR has undoubtedly increased substantially across the country—so where are all the court cases? If this were as black-and-white as FWS makes it sound, there wouldn’t even be a discussion about TNR (and the Urban Wildlands Group would likely have taken a very different tack in its opposition to TNR in Los Angeles).

Summary
There is no doubt that the Florida Keys are immensely valuable for their diversity of animal and plant life, some of which can be found nowhere else in the world. Due to a wide range of factors—most of them human-caused—this habitat has become quite fragile, with some animal and plant species on the brink of extinction. Ecosystems—especially those as fragile as the Keys—are incomprehensibly complex, and tinkering with them is incredibly risky. And there’s plenty we simply do not know, and cannot—despite our best efforts—predict.

In its attempt to eliminate free-roaming cats from the Keys, FWS overlooks several important factors, thereby imposing a greater risk to the very native wildlife it aims to protect.

The IPMP/EA proposed by FWS fails to adequately address (1) the presumed impacts of free-roaming cats on native wildlife in the Keys, and (2) the risks inherent with the improper management of these cats. It’s easy to imagine the losers in the deal—the cats, obviously, but also all of the wildlife FWS wants to protect. And the taxpayers, too, of course—this promises to be a dismal return on investment for all of us, no matter what our position might be on feral cats, wildlife conservation, and the like. The question is, where are the winners?

I strongly encourage FWS to revise its IPMP/EA, paying particular attention to these two issues, and to give further consideration to TNR in light of these and other important factors outlined in this letter.

Respectfully,

Peter J. Wolf
Independent Researcher/Analyst
www.VoxFelina.com

Literature Cited

1. n.a., Draft Environmental Assessment: Florida Keys National Wildlife Refuges Complex Integrated Predator Management Plan. 2011, U.S. Fish & Wildlife Service: Big Pine Key, FL. http://www.fws.gov/nationalkeydeer/predatormgmt.html

http://www.fws.gov/nationalkeydeer/pdfs/USFWS%20FL%20Keys%20Refuges%20Integrated%20Predator%20Mgmt%20Plan%20&%20EA%20FINAL%20DRAFT.pdf

2. Cruz, J.B. and Cruz, F., “Conservation of the dark-rumped petrel Pterodroma phaeopygia in the Galápagos Islands, Ecuador.” Biological Conservation. 1987. 42(4): p. 303-311. http://www.sciencedirect.com/science/article/B6V5X-48XKMBP-17J/2/f81b57e317f217802d9aca8b6927a88c

3. Kirkpatrick, R.D. and Rauzon, M.J., “Foods of Feral Cats Felis catus on Jarvis and Howland Islands, Central Pacific Ocean.” Biotropica. 1986. 18(1): p. 72-75. http://www.jstor.org/stable/2388365

4. Calver, M., et al., “Reducing the rate of predation on wildlife by pet cats: The efficacy and practicability of collar-mounted pounce protectors.” Biological Conservation. 2007. 137(3): p. 341-348. http://www.sciencedirect.com/science/article/B6V5X-4NGBB7H-3/2/456180347a2c3916d1ae99e220dd329e

5. Coleman, J.S. and Temple, S.A., “Rural Residents’ Free-Ranging Domestic Cats: A Survey.”Wildlife Society Bulletin. 1993. 21(4): p. 381–390. http://www.jstor.org/pss/3783408

6. Churcher, P.B. and Lawton, J.H., “Predation by domestic cats in an English village.” Journal of Zoology. 1987. 212(3): p. 439-455. http://dx.doi.org/10.1111/j.1469-7998.1987.tb02915.x

7. n.a., State of the Birds, United States of America, 2009. 2009, U.S. Department of Interior: Washington, DC. p. 36. http://www.stateofthebirds.org/

www.stateofthebirds.org/pdf_files/State_of_the_Birds_2009.pdf

8. Hawkins, C.C., Impact of a subsidized exotic predator on native biota: Effect of house cats (Felis catus) on California birds and rodents. 1998, Texas A&M University

9. Jessup, D.A., “The welfare of feral cats and wildlife.” Journal of the American Veterinary Medical Association. 2004. 225(9): p. 1377-1383. http://www.ncbi.nlm.nih.gov/pubmed/15552312

http://www.avma.org/avmacollections/feral_cats/javma_225_9_1377.pdf

10. Stallcup, R., “A reversible catastrophe.” Observer 91. 1991(Spring/Summer): p. 8–9. http://www.prbo.org/cms/print.php?mid=530

http://www.prbo.org/cms/docs/observer/focus/focus29cats1991.pdf

11. Sax, D.F. and Gaines, S.D., Species invasions and extinction: The future of native biodiversity on islands, in In the Light of Evolution II: Biodiversity and Extinction,. 2008: Irvine, CA. p. 11490–11497. www.pnas.org/content/105/suppl.1/11490.full

http://www.pnas.org/content/105/suppl.1/11490.full.pdf

12. Elliott, J. (1994, March 3–16). The Accused. The Sonoma County Independent, pp. 1, 10.

13. Coleman, J.S. and Temple, S.A., On the Prowl, in Wisconsin Natural Resources. 1996, Wisconsin Department of Natural Resources: Madison, WI. p. 4–8. http://dnr.wi.gov/wnrmag/html/stories/1996/dec96/cats.htm

14. Coleman, J.S. and Temple, S.A., How Many Birds Do Cats Kill?, in Wildlife Control Technology. 1995. p. 44. http://www.wctech.com/WCT/index99.htm

15. Mitchell, J.C. and Beck, R.A., “Free-Ranging Domestic Cat Predation on Native Vertebrates in Rural and Urban Virginia.” Virginia Journal of Science. 1992. 43(1B): p. 197–207. www.vacadsci.org/vjsArchives/v43/43-1B/43-197.pdf

16. Baker, P.J., et al., “Cats about town: is predation by free-ranging pet cats Felis catus likely to affect urban bird populations?“ Ibis. 2008. 150: p. 86-99. http://www.ingentaconnect.com/content/bsc/ibi/2008/00000150/A00101s1/art00008

17. Møller, A.P. and Erritzøe, J., “Predation against birds with low immunocompetence.” Oecologia. 2000. 122(4): p. 500-504. http://www.springerlink.com/content/ghnny9mcv016ljd8/

18. Soulé, M.E., et al., “Reconstructed Dynamics of Rapid Extinctions of Chaparral-Requiring Birds in Urban Habitat Islands.” Conservation Biology. 1988. 2(1): p. 75–92. http://www.jstor.org/pss/2386274

http://deepblue.lib.umich.edu/bitstream/2027.42/74761/1/j.1523-1739.1988.tb00337.x.pdf

19. Crooks, K.R. and Soulé, M.E., “Mesopredator release and avifaunal extinctions in a fragmented system.” Nature. 1999. 400(6744): p. 563–566. http://www.nature.com/nature/journal/v400/n6744/abs/400563a0.html

20. Fitzgerald, B.M., Karl, B.J., and Veitch, C.R., “The diet of feral cat (Felis catus) on Raoul Island, Kermadec group.” New Zealand Journal of Ecology. 1991. 15(2): p. 123–129. http://www.feral.org.au/the-diet-of-feral-cats-felis-catus-on-raoul-island-kermadec-group/

www.newzealandecology.org.nz/nzje/free_issues/NZJEcol15_2_123.pdf

21. Fan, M., Kuang, Y., and Feng, Z., “Cats protecting birds revisited.” Bulletin of Mathematical Biology. 2005. 67(5): p. 1081–1106. http://www.springerlink.com/content/p0h5854n56183874/

22. Courchamp, F., Langlais, M., and Sugihara, G., “Cats protecting birds: modelling the mesopredator release effect.” Journal of Animal Ecology. 1999. 68(2): p. 282–292. http://dx.doi.org/10.1046/j.1365-2656.1999.00285.x

http://deepeco.ucsd.edu/~george/publications/99_cats_protecting.pdf

23. Bergstrom, D.M., et al., “Indirect effects of invasive species removal devastate World Heritage Island.” Journal of Applied Ecology. 2009. 46(1): p. 73-81. http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2664.2008.01601.x/abstract

http://eprints.utas.edu.au/8384/4/JAppEcol_Bergstrom_etal_journal.pdf

24. n.a., Multi-Species Recovery Plan for South Florida: Lower Keys Rabbit. 1999, U.S. Fish and Wildlife Service: Atlanta, GA. p. 151–171. http://www.fws.gov/verobeach/index.cfm?Method=programs&NavProgramCategoryID=3&programID=107&ProgramCategoryID=3

www.fws.gov/verobeach/images/pdflibrary/lkmr.pdf

25. n.a., Multi-Species Recovery Plan for South Florida: Key Largo Cotton Mouse. 1999, U.S. Fish and Wildlife Service: Atlanta, GA. p. 79–96. http://www.fws.gov/verobeach/index.cfm?Method=programs&NavProgramCategoryID=3&programID=107&ProgramCategoryID=3

http://www.fws.gov/verobeach/images/pdflibrary/klcm.pdf

26. n.a., Key Largo Cotton Mouse (Peromyscus gossypinus allapaticola) 5-Year Review: Summary and Evaluation. 2009, U.S. Fish and Wildlife Service, Southeast Region, South Fiorida Ecological Services Office: Veero Beach, FL. p. 19. http://ecos.fws.gov/speciesProfile/profile/speciesProfile.action?spcode=A086

http://ecos.fws.gov/docs/five_year_review/doc2378.pdf

27. n.a., Multi-Species Recovery Plan for South Florida: Key Largo Woodrat. 1999, U.S. Fish and Wildlife Service: Atlanta, GA. p. 195–216. http://www.fws.gov/verobeach/index.cfm?Method=programs&NavProgramCategoryID=3&programID=107&ProgramCategoryID=3

http://www.fws.gov/verobeach/images/pdflibrary/klwr.pdf

28. n.a., Key Largo Woodrat (Neotomafloridana smalli) 5-Year Review: Summary and Evaluation. 2008, U.S. Fish and Wildlife Service, Southeast Region, South Fiorida Ecological Services Office: Vero Beach, FL. http://ecos.fws.gov/speciesProfile/profile/speciesProfile.action?spcode=A087

http://www.ecos.fws.gov/docs/five_year_review/doc1985.pdf

29. n.a., Multi-Species Recovery Plan for South Florida: Rice Rat. 1999, U.S. Fish and Wildlife Service: Atlanta, GA. p. 173–194. http://www.fws.gov/verobeach/index.cfm?Method=programs&NavProgramCategoryID=3&programID=107&ProgramCategoryID=3

http://www.fws.gov/verobeach/images/pdflibrary/srra.pdf

30. n.a., Rice rat (Oryzomys palustris natator) 5-Year Review: Summary and Evaluation. 2008, U.S. Fish and Wildlife Service, Southeast Region, South Florida Ecological Services Office: Vero Beach, FL. http://ecos.fws.gov/speciesProfile/profile/speciesProfile.action?spcode=A083

http://ecos.fws.gov/docs/five_year_review/doc1958.pdf

31. Winograd, N.J., Redemption: The myth of pet overpopulation and the no kill revolution in America. 2007: Almaden Books. http://www.nathanwinograd.com/?page_id=164

32. n.a., Feral and Free-Ranging Cat Trapping by the USDA, APHIS, Wildlife Services (WS) on North Key Largo. 2004, U.S. Department of Agriculture

33. O’Hara, T. (2007, April 3). Fish & Wildlife Service to begin removing cats from Keys refuges. The Key West Citizen, from http://keysnews.com/archives

34. n.a., Lower Florida Keys National Wildlife Refuges Comprehensive Conservation Plan. 2009, U.S. Department of the Interior, Fish and Wildlife Service: Atlanta, GA. http://www.fws.gov/nationalkeydeer/

http://www.fws.gov/southeast/planning/PDFdocuments/Florida%20Keys%20FINAL/TheKeysFinalCCPFormatted.pdf

35. Nogales, M., et al., “A Review of Feral Cat Eradication on Islands.” Conservation Biology. 2004. 18(2): p. 310–319. http://onlinelibrary.wiley.com/doi/10.1111/j.1523-1739.2004.00442.x/abstract

36. Veitch, C.R., “The eradication of feral cats (Felis catus) from Little Barrier Island, New Zealand.”New Zealand Journal of Zoology. 2001. 28: p. 1–12. http://www.royalsociety.org.nz/publications/journals/nzjz/2001/001/

http://www.royalsociety.org.nz/media/publications-journals-nzjz-2001-001.pdf

37. Andersen, M.C., Martin, B.J., and Roemer, G.W., “Use of matrix population models to estimate the efficacy of euthanasia versus trap-neuter-return for management of free-roaming cats.” Journal of the American Veterinary Medical Association. 2004. 225(12): p. 1871–1876. http://www.avma.org/avmacollections/feral_cats/default.asp

http://www.avma.org/avmacollections/feral_cats/javma_225_12_1871.pdf

38. Calhoon, R.E. and Haspel, C., “Urban Cat Populations Compared by Season, Subhabitat and Supplemental Feeding.” Journal of Animal Ecology. 1989. 58(1): p. 321–328. http://www.jstor.org/pss/5003

39. Castillo, D. and Clarke, A.L., “Trap/Neuter/Release Methods Ineffective in Controlling Domestic Cat “Colonies” on Public Lands.” Natural Areas Journal. 2003. 23: p. 247–253.

40. Natoli, E., et al., “Management of feral domestic cats in the urban environment of Rome (Italy).”Preventive Veterinary Medicine. 2006. 77(3-4): p. 180-185. http://www.sciencedirect.com/science/article/B6TBK-4M33VSW-1/2/0abfc80f245ab50e602f93060f88e6f9

www.kiccc.org.au/pics/FeralCatsRome2006.pdf

41. Levy, J.K. and Crawford, P.C., “Humane strategies for controlling feral cat populations.” Journal of the American Veterinary Medical Association. 2004. 225(9): p. 1354–1360. http://www.avma.org/avmacollections/feral_cats/default.asp

http://www.avma.org/avmacollections/feral_cats/javma_225_9_1354.pdf

42. Levy, J.K., Personal communication, 2010.

43. Hatley, P.J., Feral Cat Colonies in Florida: The Fur and the Feathers Are Flying. 2003, University of Florida Conservation Clinic: Gainsville, FL. http://www.animallaw.info/articles/arus18jlanduseenvtll441.htm

www.law.ufl.edu/conservation/pdf/feralcat.pdf

Operation Sisyphus

13 Jan 2011•In the News, Threats to Wildlife

The draft environmental assessment (EA) for the Florida Keys National Wildlife Refuges Complex Integrated Predator Management Plan (download PDF), released last week by the U.S. Fish and Wildlife Service (FWS), aims to eliminate free-roaming cats in the Keys. Not that this is anything new—FWS (along with USDA, and some state agencies) has been trying to do this for years now.

Plans include the trapping/removal of free-roaming cats—owned and unowned alike—from refuge lands and other public lands nearby, as well as from other land (including private property) where cats may be considered a threat to vulnerable native species. TNR has been dismissed as an option, and FWS proposes to prohibit the feeding of feral cats wherever possible.

Unfortunately, the proposed plan is unlikely to be any more successful than previous efforts. There’s plenty to dislike about the FWS plan—including the risk that it may set a dangerous precedent nationwide. The deadline for public comments (see Plan for details) is February 3.

Justification or Rationalization?
In a section of the document called Justification for Management Action, FWS lays out their numerous grievances against “non-native species and human-subsidized populations of native predators.” [1] As a review of the relevant literature, the sub-section on domestic cats leaves much to be desired is a train wreck.

In fact, if this were a college-level term paper, it would likely receive a failing grade—followed, perhaps, by disciplinary action. (And, if it were allowed under the law, maybe a drug test, too.)

Science
Among the references cited here (about three-quarters of which I’m familiar; the rest I’m still chasing down) is, admittedly, some rather damning evidence. For example:

The near-extirpation of rock iguanas from Pine Cay in the Caicos Islands during the 1970s. “The decline, from an estimated adult lizard population of nearly 5,500, was due primarily to predation by domestic dogs and cats introduced to the island simultaneously with hotel construction.” [2] (Strangely, FWS cites Iverson’s paper not as an example of a near-miss, but of a global extinction. This, however, pales in comparison to the “strangeness” of many of their other citations.)
On Little Barrier Island, off the coast of New Zealand, cats “were considered to have been the sole cause of the local eradication of North Island saddleback and to have contributed to the extinction of the Little Barrier snipe, and to threaten, by their continued presence, grey-faced, black, and Cook’s petrels. Cats probably also contributed to the decline of tuatara and the 12 lizard species known to be present on Little Barrier Island.” [3]

Sci-Fi
On the other hand, much of the FWS’s evidence is, at best, circumstantial. Among the studies cited to support their claim that “free-roaming cats have been shown to be a major cause of 33 native species extinction [sic] globally,” is a 1987 paper by Cruz and Cruz, in which the authors, studying Galápagos Petrels, found that cats were hardly the only culprits:

“They are threatened by introduced rats, which attack eggs and young chicks… dogs and pigs which prey on eggs, nestlings and adults. Introduced goats, burros and cattle destroy nesting habitat and trample nests. A different combination of these pests and predators exists at each of the petrel nesting sites, while three of the islands are plagued by all of them.” [4]

And, as with the rock iguanas, the FWS would have the public believe the Galápagos Petrel is among those 33 extinctions. In fact, the birds are still there, though they are listed as Critically Endangered.

The story is similar for the 1986 paper by Kirkpatrick and Rauzon, another purported link between free-roaming cats and species extinctions. Kirkpatrick and Rauzon found that more than 90 percent of the diet of free-roaming cats on Jarvis Island and Howland Island was made up of Sooty Terns, Wedge-tailed Shearwaters, and Brown Noddies —each of which is listed as a species of Least Concern.

Another of the papers cited by FWS has nothing to do with extinctions at all. As the authors themselves describe it, their study was an evaluation of “whether a collar-worn pounce protector, the CatBib, reduces the number of vertebrates caught by pet cats and whether its effectiveness was influenced by colour or adding a bell.” [5]

FWS argues that “many of the species impacted by free-roaming cats are federally listed threatened or endangered species and federally protected migratory birds.” While probably true, this statement is also largely meaningless. According to the 2009 State of the Birds report, published by the Department of the Interior (which oversees FWS):

“The United States is home to a tremendous diversity of native birds, with more than 800 species inhabiting terrestrial, coastal, and ocean habitats, including Hawaii. Among these species, 67 are federally listed as endangered or threatened. An additional 184 are species of conservation concern because of their small distribution, high threats, or declining populations.” [6]

That translates to approximately 31 percent of all birds in this country being species of concern. FWS makes it sounds as if perhaps the cats are targeting these birds; in fact, they could just as easily have claimed that many of the species impacted by all forms of mortality are federally listed threatened or endangered species and federally protected migratory birds of these birds.

Hang in there, though—it gets better. I mean worse.

Fantasy
Also listed among the evidence of island extinctions were Coleman and Temple’s 1993 survey of rural Wisconsin residents about their outdoor cats [7], and Churcher and Lawton’s “English Village” study [8]. (While England is an island, it’s quite a stretch to suggest that Felmersham’s House sparrows are at risk of extinction.)

When it comes to the disruption caused by cats to “the abundance, diversity, and integrity of native ecosystems,” FWS turns to, among others, studies by Hawkins [9] and Jessup. [10]

As I’ve discussed previously, Hawkins’ dissertation work was plagued with problems that raise serious doubts about his rather triumphant conclusions—“the preference of ground feeding birds for the no-cat treatment was striking,” [9] for example. A closer look reveals that five of the nine ground-feeding birds showed no preference for either area of the study site. One could, based on Hawkins’ findings, just as easily conclude that more than half of the ground-feeding species studied were indifferent to the presence of cats.

Jessup cites some well-known predation studies, but his concern is the condemnation of “trap, neuter, and reabandon,” [10] as he calls it (“Abandonment of animals cannot be morally justified and is illegal under state humane laws… If it is illegal to abandon a cat once, how can it be legal to do it a second time? How can veterinarians justify being party to abandonment, an illegal act of animal cruelty?” [10])

FWS suggests that “free-roaming cats kill at least one billion birds every year in the U.S., representing one of the largest single sources of human-influenced mortality for small native wildlife,” [1] supporting their assertion with just three sources, one of which is Rich Stallcup’s 1991 article from the Observer, a publication of the Point Reyes Bird Observatory. But “A Reversible Catastrophe” is very light on science—and Stallcup gets most of that wrong. Mostly, the article is Stallcup’s manifesto regarding neighborhood cats:

“If you have a garden, why not proclaim it a wildlife sanctuary and protect it from non-native predators? If roaming cats come into your sanctuary to poach the wildlife under your stewardship, you have the right and perhaps even the duty to discourage them in a serious way.” [11]

Discourage them? Among Stallcup’s suggestions: “…try a B-B or pellet gun. There is no need to kill or shoot toward the head, but a good sting on the rump seems memorable for most felines, and they seldom return for a third experience.” [11]

No feral cat witch hunt would be complete without some public health threat fear-mongering, and FWS’s plan is no different:

“According to the Centers for Disease Control (CDC), free-roaming cats not only threaten wildlife through direct predation but also serve as vectors for a number of diseases including rabies, cat scratch fever, hookworms, roundworms and toxoplasmosis. Some of these diseases can be transmitted to other domestic animals, native wildlife, and in some cases, humans.” [1]

But the CDC site makes no mention of cats being a threat to wildlife. And humans? “Although cats can carry diseases and pass them to people, you are not likely to get sick from touching or owning a cat.” And, notes the CDC, “People are probably more likely to get toxoplasmosis from gardening or eating raw meat than from having a pet cat.”

There’s even a link to another page on the CDC’s site, called “Health Benefits of Pets.”

And finally, there’s the paper by Sax and Gaines. If the previous examples miss their mark, this one’s a full-blown non-sequitur. Though the authors do mention “the extinction of many native animal species on islands” [12] briefly in their introduction, the purpose of the paper is, as the authors state plainly enough, to “show that the number of naturalized plant species has increased linearly over time on many individual islands.” [12, emphasis mine]

• • •

FWS intends to eliminate free-roaming cats from the Florida Keys, and this is the best they can do? If so, well, perhaps they ought to be doing something else. If this is their “justification for action,” then any subsequent action can, I think, rightfully be considered unjustified.

Predator Management
Among the animals to be monitored throughout and/or removed from the four refuges that make up the Florida Keys National Wildlife Refuges Complex (National Key Deer Refuge, Key West National Wildlife Refuge, Great White Heron National Wildlife Refuge, and Crocodile Lake National Wildlife Refuge) are non-native reptiles and rodents, native raccoons, and, of course, the cats.

“Presence of exotic non-native iguanas, lizards, and large-bodied snakes will be detected through reports, incidental sightings, and the community-based interagency ‘Python Patrol’ network. Exotic reptiles will be immediately dispatched in accordance with AVMA guidelines for humane euthanasia.” [1]

“Any non-native opossum, armadillo, or rat caught incidentally in the live traps targeted for cats on Refuge lands will be immediately dispatched in accordance with the American Veterinary Medical Association (AVMA) guidelines for humane euthanasia. All native species will be immediately set free.” [1, emphasis mine]

“Raccoons trapped incidentally in live traps targeted for cats or other non-native predators will be released alive at the trap location… Raccoons that exhibit severe disease or other serious health issues will receive appropriate evaluation, which may include care by a state-certified wildlife rehabilitator or euthanasia as recommended by a qualified veterinarian or animal control services provider… If field studies and monitoring indicate that raccoon populations are having a negative impact on endangered species, the USFWS will reevaluate the need to implement more direct control by removal of raccoons from sensitive habitats. Removal could include, but not be limited to, transfer to a wildlife park or zoo, a state-certified wildlife rehabilitator, or euthanasia. Any decision by the Service to use lethal control measures on raccoons will trigger additional public notification and an amendment to this EA.” [1]

Free-roaming Cats
But, as I say, the cats are the real focus here: “The USFWS will remove all free-roaming cats found on Refuge lands through live trapping,” at which point, the cats will become of the responsibility of any one of three (currently, two; a third contractor is currently being sought) Monroe County animal control providers.

“The Monroe County animal control service provider will have the authority to determine the final disposition of the trapped cats according to county ordinances and standards, which may include returning to owner, adopting out, relocating to a long-term cat care facility on the mainland, or euthanizing.” [1]

Of course, it’s no secret what happens to the vast majority of feral cats brought into shelters. As Nathan Winograd writes in his book Redemption: The Myth of Pet Overpopulation and the No Kill Revolution in America, “there is no other animal entering a shelter whose prospects are so grim and outcome so certain.”

I asked Connie Christian, Executive Director of the Florida Keys SPCA, about this last week. “Every cat brought to our facility is assessed to determine their disposition,” Christian told me via e-mail. “Every attempt is made to return ‘non-feral’ cats to their owners or place for adoption.”

“Unfortunately,” she continued, “we do not have an outlet for feral cats that are brought to us without a request for return.” Which would likely be the case for cats unlucky enough to be trapped by FWS. (Interestingly, FKSPCA is involved with TNR, which FWS wants to eliminate—more on that in a moment.)

What about that “relocation to long-term facilities on the mainland” option? There was some discussion of this option during stakeholder meetings that took place in 2008. And local papers carried stories suggesting the possibility. [13, 14] Now it looks like FWS is dumping this is the laps of Monroe County animal control providers.

I guess they can say they tried.

Expanding Territory
But FWS isn’t stopping at their property line—and the four refuges included in the plan already make up, according to my calculations, more than 28 percent of the Keys’ total land mass. According to the South Florida Multi-Species Recovery Plan (MSRP), FWS has plans to use land acquisition and conservation easements or agreements to protect the endangered Lower Keys marsh rabbit. [15]

The MSRP, excerpts of which are included in the EA, also spells out FWS’s intention to “remove nuisance feral cats” from land “near rabbit habitat” in the Lower Keys. [1] Additional plans include deed restrictions “to prohibit free-roaming cats” [1] in areas where they might be a threat to the rabbits, the Key Largo Woodrat, or the Key Largo Cotton Mouse . And to “enforce deed restrictions of cat control in Ocean Reef Club and other areas.” [1]

The Ocean Reef Club, of course, is home to ORCAT, perhaps the best known—and certainly one of the most successful—TNR programs in the country. According to their website, ORCAT has reduced the island’s population of cats from approximately 2,000 cats, in the early 1990s, to about 350 today, “about 100 of which reside at the Grayvik Animal Care Center.”

Frankly, I’m not sure what FWS means by “enforce deed restrictions” (one of many follow-up items on my to-do list). Other aspects of their plan, however, are straightforward:

“Feral cat colonies and feeding stations on Refuge lands will be identified and removed. The USFWS will also coordinate with county and state agencies to assist in the identification and removal, where feasible and legal, cat colonies and feeding stations on other public properties that are adjacent to or near Refuge lands. Extensive public outreach will be conducted to encourage people who feed free-roaming cats to cease doing so, and to promote trapping and relocating those animals to long-term facilities on the mainland where they will no longer be a threat to Refuge’s wildlife.” [1]

Something else that’s clear: FWS is going after pet cats, too. The MSRP includes plans to “establish a program to license domestic cats, implement leash laws, eliminate cat-feeding stations, implement spay and neuter program, increase awareness through educational material, test diseases, and remove nuisance feral cats.” [15]

Is this mandatory spay/neuter (which has been shown to fail when implemented in the absence of adequate low- and no-cost services)? Does the FWS plan to test pets for, say FIV and FeLV? Lots of unanswered questions here, obviously.

Trap-Neuter-Return
It’s no surprise, then, given their plan for the removal of feeding stations—and cats—that FWS is staunchly opposed to TNR, which, they argue “does little to reduce cat predation on native wildlife.” [1]

Success Stories
“In addition,” argues FWS, “the TNR method has little valid scientific support for claims that it actually reduces cat colony numbers over time and often has been shown to attract people to release new cats into an area.” [1]

Ironically, some of the greatest TNR success stories are right there in the papers cited by FWS. Natoli, for example, reported a 16–32 percent decrease in population size over a 10-year period across 103 colonies in Rome—despite a 21 percent rate of “cat immigration.” [16]

Castillo and Clarke, though highly critical of TNR documented remarkably little predation in the two Florida parks they used for their study. In fact, over the course of approximately 300 hours of observation (this, in addition to “several months identifying, describing, and photographing each of the cats living in the colonies” [17] prior to beginning their research), Castillo and Clarke “saw cats kill a juvenile common yellowthroat and a blue jay.” [17]

“Cats also caught and ate green anoles, bark anoles, and brown anoles. In addition, we found the carcasses of a gray catbird and a juvenile opossum in the feeding area.” [17]

Any TNR program contends with the unfortunate (and illegal) dumping of cats. Still, it’s difficult to imagine that the presence or absence of a nearby TNR program would affect a person’s decision to abandon his/her pet cat(s). (If any studies had demonstrated such a connection, TNR opponents would surely cite them!) On the other hand, cats dumped near a managed colony are far more likely to be adopted and/or sterilized—thereby mitigating their potential impact on the overall population of unowned cats—as well any impacts to wildlife and the environment.

“It is quite obvious that cats can be lethal to birds,” writes Hatley, “and if the death of a migratory bird can be traced to a cat, or a cat colony, which can be further traced to an individual or organization, there may be strict liability for that person under the MBTA.” [19] Hatley’s argument for violations of the Endangered Species Act is similarly speculative: “…persons who release cats into the wild or who maintain feral cat colonies could be found liable for a take under section 9 of the ESA if maintenance of feral cats in the wild is found to kill or injure wildlife by degrading habitat.” [19]

PETA
Finally—perhaps in a desperate attempt to appear as though their plan has the support of animal welfare organizations—FWS gives PETA a plug.

“Some animal advocates therefore often agree that traditional TNR programs are not the most appropriate choice, especially where cats are released near designated wildlife areas and at-risk wildlife populations (see the People for the Ethical Treatment of Animals’ Animal Rights Uncompromised fact sheets at www.peta.org/about/why-peta/default.aspx). For these reasons, TNR was considered but dismissed from further evaluation.” [1]

PETA, of course, is also opposed to caged birds, crating dogs, and zoos. When PETA is the only “animal advocate” you can get to endorse your approach, it’s time to rethink it.

Operation Sisyphus
The purpose of FWS’s Plan/EA “is to conserve and restore federally-listed species and protect all native fauna and flora on the [refuges] from population decline and potential extirpation or extinction due to predation by non-native species and human-subsidized populations of native predators.” [1]

Will the plan work? Only time will tell, of course—but there’s plenty of reason for skepticism. If their “literature review” is any indication, FWS either doesn’t have a particularly strong grasp of the issues involved—or they’re not interested in sharing that understanding with the public.

Nitpicking? I don’t think so. In their attempt to focus—however carelessly—on the impacts of cats, FWS overlooks some key factors.

Mesopredator Release
FWS refers to two often-cited papers [20, 21] as evidence of cats disrupting native ecosystems, but fails to acknowledge the larger point made by the authors: the mesopredator release phenomenon. “In the absence of large, dominant predators,” write Soulé et al., “smaller omnivores and predators undergo population explosions, sometimes becoming four to 10 times more abundant than normal.” [20]

In Soulé’s example, coyotes were the dominant predators, while cats were the mesopredators. In other contexts, however, cats have been shown to play the dominant predator role with rats becoming the mesopredators.

Could something like this happen in the Florida Keys?

But controlling these rats is complicated considerably by the need to protect Lower Keys marsh rabbits. The MSRP warns of these rabbits coming into contact with pesticides and “poisons used to control black rats.” [15]

“In a 1993 Biological Opinion, the FWS investigated the effects of vertebrate control agents on endangered and threatened species and determined that several chemicals (e.g., Pival) would jeopardize the continued existence of the Lower Keys marsh rabbit. Chemicals—such as Pival—a rodenticide used to kill rats, are lethal if ingested. The FWS also concluded that if development in the Keys continues to increase, the potential for these animals to come in contact with such chemicals also increases, as does the potential for their extinction. Based on these findings, the FWS believes the continued use of such chemicals will result in the deaths of Lower Keys marsh rabbits. Given that the majority of occupied habitat is adjacent to urbanized areas, and that urbanization continues to expand into their habitat, then it can reasonably be predicted that the use of such chemicals has had a negative impact upon the Lower Keys marsh rabbit that may prevent its recovery.” [15]

Removing Cats
It’s also not clear that FWS will be able to remove the free-roaming cats from the Keys. For one thing, they have no idea how many are there. Only now—after years of struggling with this issue—does FWS propose to “implement monitoring and conduct further research as needed to determine abundance and distribution of free-roaming cats throughout the Refuge, document effectiveness of management actions taken or not taken on cat populations, and determine the impacts on the ecosystems and native species to aid in the adaptive management process.” [1]

Plus, FWS has a rather poor track record when it comes to actually trapping cats.

In 2007, they “received $50,000 to remove cats from federal refuges on Big Pine Key and Key Largo, and to protect endangered marsh rabbits, silver rice rats and other animals and birds that call the refuges home.” [25] Reports (from what I can tell, nothing official has been issued) suggest that fewer than 20 cats were caught—some of which were returned to their owners (kudos to FWS and USDA)—along with 81 raccoons, 53 of which were released alive. [26]

I think it’s safe to say that the Keys’ wildlife reaped little or no benefit from this effort. Had that same money been used for TNR, on the other hand…

So what’s different this time around?

Déjà Vu
All the while I’ve been doing the research for this post, I’ve been haunted by two quotes I’ve used rather extensively in the past. Actually, the first is not a quote as such, but the title of Merritt Clifton’s excellent article: Where cats belong—and where they don’t. [27]

The second comes from Gary Patronek, who argues that “the release of cats into an environment where they would impact endangered or threatened species, or even into wildlife preserves or refuges, is inexcusable.” [28] Patronek, the former Director of the Center for Animals and Public Policy at the Cummings School, and one of the founders of the Hoarding of Animals Research Consortium, continues:

“I do not believe that this is being advocated by cat protectors who see urban, managed colonies as an imperfect but still preferable alternative to the euthanasia of healthy animals. Abandoned pet cats whose own habitat has been reduced to colonies, and the wild species endangered by clear-cutting or beachfront development, are casualties of the same callous disregard for the lives of animals. I see little justification for shifting the role of cats to that of scapegoat.” [28, emphasis mine]

Well, isn’t this precisely what I’m advocating? I honestly don’t know.

Here’s what I do know:

There is no doubt that the Florida Keys are immensely valuable for their diversity of animal and plant life, some of which can be found nowhere else in the world. Due to a wide range of factors (most of them human-caused), this habitat has become quite fragile, with some animal and plant species on the brink of extinction. And, in such habitats, it’s been shown that free-roaming cats can have a significant negative impact.

I also know that where cats have been eradicated, the process is a horror. In fact, it’s spelled out in some of the papers cited by FWS (though, understandably, they don’t draw attention to that):

Nogales et al., describing the “success” of Marion Island, note, “it took about 15 years of intense effort to eradicate the cats, combining several methods such as trapping, hunting, poisoning, and disease introduction… The use of disease agents or targeted poisoning campaigns hold promise for an initial population reduction in eradication programs on large islands—such an approach may save effort, time, and money.” [29]

Cruz and Cruz point out that, of all the non-native mammals there, cats were “the most difficult to control or eliminate on Floreana Island.” Although “hunting with dogs was the single most effective method employed and it gave a sure body count,” the authors warn that “the method was costly and with the limited manpower available was only useful over small areas. Both poisoning and trapping were effective and the combination of the three methods is probably the most effective approach, as well as being the best use of time and materials.” [4]

Veitch describes efforts on 11-square-mile Little Barrier Island as “a determined [cat] eradication attempt” involving “cage traps, leg-hold traps, dogs and 1080 poison were used, but leg-hold traps and 1080 poison were the only effective methods.” [3] Four cats were also infected with Feline enteritis, but “because of the poor reaction to the virus no other cats were dosed and none were released… Altogether, 151 cats were known to have been killed before the eradication was declared complete. Important lessons learnt can be transferred to other feral cat eradication programmes.” [3] (By way of comparison, the Keys are approximately 137 square miles in total area.)

I know that ecosystems—especially those as fragile as the Keys—are incomprehensibly complex, and that tinkering with them is incredibly risky. And there’s plenty we simply do not know, and cannot—despite our best efforts—predict.

But I know, too, that time is short. And that we’ll never have all the answers we’d like to have before the need for action precludes further inquiry.

Implementation
Put another way: I’ve given this issue a lot of thought—and, here’s what I’m afraid will happen in the Keys:

FWS will proceed with their plan, rounding up cats—ferals and pets alike—on and “near” public lands. The pet cats will mostly be returned, but some mistakes—the risk of which will likely increase in an atmosphere of mass trapping—will surely be made. Feral cats will be killed.

Progress will move slowly, as these things often do—far too slowly to keep up with reproduction rates. If feeding and TNR are eliminated (to whatever extent possible) throughout the Keys, the cats will simply “go underground.” No more monitoring—and sterilizing—by the “foot soldiers” who currently care for colonies of cats.

Indeed, it’s quite likely that feral cat complaint calls to Monroe County, FWS, and the USDA would taper off considerably, as it becomes clear that such a call is essentially a death sentence. Thus, the cats become that much more difficult to locate—and sterilize. The population, therefore, increases.

Using a population model, Andersen, Martin, and Roemer have suggested that, in the absence of a sterilization program, 50 percent of cats would have to be removed in order for a colony to decrease 10 percent annually. [30] By contrast, the authors suggest that 75 percent of cats would need to be sterilized to achieve the same result.

This model has its flaws, as I’ve explained elsewhere, but the study is one many researchers are familiar with. And, frankly, it’s convenient for my purposes here.

Even if Andersen et al. are off by a factor of two, FWS would need to “remove” 25 percent of the free-roaming, unsterilized (and once they chase away the colony caretakers, it won’t be long before that’s the norm) cats continuously in order to achieve a 10 percent reduction in overall numbers.

Does anybody really think that’s going to happen? Where’s the evidence to suggest that it’s even possible?

FWS has—it seems—taken off the table the unspeakable methods so often employed on small, uninhabited islands.

“While lethal control is allowed by Refuge System policy, it is not a socially acceptable approach and is inconsistent with the points of consensus developed by the stakeholder group. This alternative would likely not be logistically feasible on a FKNWRC-wide basis and would not allow for adaptive management under a strategic habitat conservation approach.” [1]

But they’ve also taken TNR off the table. So, what’s left? We’re back to doing what we’ve been doing for years now—which, of course, is how we got into this mess in the first place.

From what I can tell, the FWS plan is nothing more than a warmed-over version of old-school trap-and-remove, an approach Mark Kumpf, president of the National Animal Control Association President from 2007 to 2008, describes as “bailing the ocean with a thimble.” [31] (There’s a metaphor that ought to resonate with people in the Keys!)

If so, it’s easy to imagine the losers in the deal—the cats, obviously, but also all of the wildlife FWS wants to protect. And the taxpayers, too, of course—not much of a return on investment for all of us, no matter what our position might be on feral cats, wildlife conservation, and the like.

The question is, where are the winners?

Literature Cited
1. n.a., Draft Environmental Assessment: Florida Keys National Wildlife Refuges Complex Integrated Predator Management Plan. 2011, U.S. Fish & Wildlife Service: Big Pine Key, FL.

2. Iverson, J.B., “The impact of feral cats and dogs on populations of the West Indian rock iguana, Cyclura carinata.” Biological Conservation. 1978. 14(1): p. 63–73. http://www.sciencedirect.com/science/article/B6V5X-48XKN72-1NN/2/bff9bfdeecb8ff6cec68527221b99a97

3. Veitch, C.R., “The eradication of feral cats (Felis catus) from Little Barrier Island, New Zealand.” New Zealand Journal of Zoology. 2001. 28: p. 1–12. http://www.royalsociety.org.nz/publications/journals/nzjz/2001/001/

4. Cruz, J.B. and Cruz, F., “Conservation of the dark-rumped petrel Pterodroma phaeopygia in the Galápagos Islands, Ecuador.” Biological Conservation. 1987. 42(4): p. 303–311. http://www.sciencedirect.com/science/article/B6V5X-48XKMBP-17J/2/f81b57e317f217802d9aca8b6927a88c

5. Calver, M., et al., “Reducing the rate of predation on wildlife by pet cats: The efficacy and practicability of collar-mounted pounce protectors.” Biological Conservation. 2007. 137(3): p. 341-348. http://www.sciencedirect.com/science/article/B6V5X-4NGBB7H-3/2/456180347a2c3916d1ae99e220dd329e

6. n.a., State of the Birds, United States of America, 2009. 2009, U.S. Department of Interior: Washington, DC. p. 36.

7. Coleman, J.S. and Temple, S.A., “Rural Residents’ Free-Ranging Domestic Cats: A Survey.” Wildlife Society Bulletin. 1993. 21(4): p. 381–390.

8. Churcher, P.B. and Lawton, J.H., “Predation by domestic cats in an English village.” Journal of Zoology. 1987. 212(3): p. 439-455. http://dx.doi.org/10.1111/j.1469-7998.1987.tb02915.x

9. Hawkins, C.C., Impact of a subsidized exotic predator on native biota: Effect of house cats (Felis catus) on California birds and rodents. 1998, Texas A&M University.

10. Jessup, D.A., “The welfare of feral cats and wildlife.” Journal of the American Veterinary Medical Association. 2004. 225(9): p. 1377-1383. http://www.avma.org/avmacollections/feral_cats/javma_225_9_1377.pdf

11. Stallcup, R., “A reversible catastrophe.” Observer 91. 1991(Spring/Summer): p. 8–9.

12. Sax, D.F. and Gaines, S.D., Species invasions and extinction: The future of native biodiversity on islands, in In the Light of Evolution II: Biodiversity and Extinction,. 2008: Irvine, CA. p. 11490–11497. www.pnas.org/content/105/suppl.1/11490.full

13. n.a. (2007, March 29). Key Deer Refuge wants to control feral cats: A plan to round up feral cats in the National Key Deer Refuge on Big Pine and No Name keys has animal-rights groups and area cat owners upset. The Reporter.

14. Busweiler, R. (2008, December 1). Feds begin drafting rabbit protection plan—BIG PINE KEY. The Key West Citizen.

15. n.a., Multi-Species Recovery Plan for South Florida: Lower Keys Rabbit. 1999, U.S. Fish and Wildlife Service: Atlanta, GA. p. 151–171. www.fws.gov/verobeach/images/pdflibrary/lkmr.pdf

16. Natoli, E., et al., “Management of feral domestic cats in the urban environment of Rome (Italy).” Preventive Veterinary Medicine. 2006. 77(3-4): p. 180-185. www.kiccc.org.au/pics/FeralCatsRome2006.pdf

17. Castillo, D. and Clarke, A.L., “Trap/Neuter/Release Methods Ineffective in Controlling Domestic Cat “Colonies” on Public Lands.” Natural Areas Journal. 2003. 23: p. 247–253.

18. Levy, J.K., Personal communication, 2010.

19. Hatley, P.J., Feral Cat Colonies in Florida: The Fur and the Feathers Are Flying. 2003, University of Florida Conservation Clinic: Gainsville, FL. www.law.ufl.edu/conservation/pdf/feralcat.pdf

20. Soulé, M.E., et al., “Reconstructed Dynamics of Rapid Extinctions of Chaparral-Requiring Birds in Urban Habitat Islands.” Conservation Biology. 1988. 2(1): p. 75-92. http://deepblue.lib.umich.edu/bitstream/2027.42/74761/1/j.1523-1739.1988.tb00337.x.pdf

21. Crooks, K.R. and Soulé, M.E., “Mesopredator release and avifaunal extinctions in a fragmented system.” Nature. 1999. 400(6744): p. 563–566. http://www.nature.com/nature/journal/v400/n6744/abs/400563a0.html

23. Fan, M., Kuang, Y., and Feng, Z., “Cats protecting birds revisited.” Bulletin of Mathematical Biology. 2005. 67(5): p. 1081-1106. http://dx.doi.org/10.1016/j.bulm.2004.12.002

24. Bergstrom, D.M., et al., “Indirect effects of invasive species removal devastate World Heritage Island.” Journal of Applied Ecology. 2009. 46(1): p. 73-81. http://eprints.utas.edu.au/8384/4/JAppEcol_Bergstrom_etal_journal.pdf

25. O’Hara, T. (2007, April 3). Fish & Wildlife Service to begin removing cats from Keys refuges. The Key West Citizen.

26. n.a., Lower Florida Keys National Wildlife Refuges Comprehensive Conservation Plan. 2009, U.S. Department of the Interior, Fish and Wildlife Service: Atlanta, GA.

27. Clifton, M. Where cats belong—and where they don’t. Animal People 2003. http://www.animalpeoplenews.org/03/6/wherecatsBelong6.03.html.

28. Patronek, G.J., “Letter to Editor.” Journal of the American Veterinary Medical Association. 1996. 209(10): p. 1686–1687.

29. Nogales, M., et al., “A Review of Feral Cat Eradication on Islands.” Conservation Biology. 2004. 18(2): p. 310-319. http://dx.doi.org/10.1111/j.1523-1739.2004.00442.x

30. Andersen, M.C., Martin, B.J., and Roemer, G.W., “Use of matrix population models to estimate the efficacy of euthanasia versus trap-neuter-return for management of free-roaming cats.” Journal of the American Veterinary Medical Association. 2004. 225(12): p. 1871-1876. http://www.avma.org/avmacollections/feral_cats/javma_225_12_1871.pdf

31. Hettinger, J., Taking a Broader View of Cats in the Community, in Animal Sheltering. 2008. p. 8–9. http://www.animalsheltering.org/resource_library/magazine_articles/sep_oct_2008/broader_view_of_cats.pdf

Adult Supervision Required

1 Dec 2010•In the News, Research Protocol, Threats to Wildlife

“Have you seen this already? This is awful.”

That’s what somebody posted on the Vox Felina Facebook page late last night—along with a link to an MSNBC news story. The headline was an attention-getter, no doubt about it: “Report: Kill feral cats to control their colonies.”

But beyond that, MSNBC had practically no details. A little digging around, however, led me to New England Cable News (NECN), which has the complete story.

“The report began in an undergraduate wildlife management class, with students writing reports on feral cats based on existing research. The students’ professor and other [University of Nebraska] researchers then compiled the report from the students’ work.” [1]

“Feral Cats and Their Management” claims, straightforwardly enough, to provide “research-based information on the management of feral cats.” [2] Management, in this case, meaning—as is so often the case in such contexts—killing, extermination, eradication, and so forth. Detailed advice is provided (e.g., “Body-gripping traps and snares can be used to quickly kill feral cats”).

And research? In this case, nothing more than a cursory review of all of the usual suspects: Coleman and Temple, Pamela Jo Hatley, Cole Hawkins, The Wildlife Society, Linda Winter. In other words, lots of Kool-Aid drinking.

It’s Like Science, Only Different
Among the research misinterpreted and/or misrepresented (none of which is cited in the text):

“As instinctive hunters, feral cats pose a serious threat to native wildlife, particularly birds.”

It’s no surprise that the authors of the report offer no evidence to support such a sweeping claim. “There are few if any studies,” write Mike Fitzgerald and Dennis Turner in their contribution to The Domestic Cat: The biology of its behaviour, “apart from island ones that actually demonstrate that cats have reduced bird populations.” [3]

Biologist C.J. Mead, reviewing the deaths of “ringed” (banded) birds reported by the British public, suggests that cats may be responsible for 6.2–31.3% of bird deaths. “Overall,” writes Mead, “it is clear that cat predation is a significant cause of death for most of the species examined.” Nevertheless, Mead concludes, “there is no clear evidence of cats threatening to harm the overall population level of any particular species… Indeed, cats have been kept as pets for many years and hundreds of generations of birds breeding in suburban and rural areas have had to contend with their predatory intentions.” [4]

The German zoologist Paul Leyhausen (1916–1998), who spent the bulk of his career studying the behavior of cats, found that cats, frustrated by the difficulties of catching them, “may soon give up hunting birds.” [5]

“During years in the field,” wrote Leyhausen, “I have observed countless times how cats have caught a mouse or a rat and just as often how they have stalked a bird. But I never saw them catch a healthy songbird that was capable of flying. Certainly it does happen, but, as I have said, seldom. I should feel sorry for the average domestic cat that had to live solely on catching birds.” [5]

“Cats kill an estimated 480 million birds per year (assuming eight birds killed per feral cat per year).”

Fitzgerald and Turner (whose work is not referenced in the report) argue that “we do not have enough information yet to attempt to estimate on average how many birds a cat kills each year.” [3] Though, of course, many studies have tried to do exactly that—few, it should be said, involve feral cats.

Unfortunately—and as I have pointed out time and time again—such work typically suffers from a range of methodological and analytical problems (e.g., statistical errors, small sample sizes, and inappropriate/baseless assumptions).

And—as with the UNL report—obvious bias.

“Estimates from Wisconsin indicate that between 500,000 and 8 million birds are killed by rural cats each year in that state…”

How anybody could misquote the numbers from the Wisconsin Study—easily the most widely circulated work on the subject—is a mystery. (On the other hand, the figures were, as Stanley Temple has said, “not actual data” [6] in the first place, so I suppose that does allow for some rather liberal interpretation.)

“The diets of well-fed house-based cats in Sweden consisted of 15 percent to 90 percent native prey, depending on availability.”

How important is it that the prey of feral cats is native, versus non-native? That’s a point of some debate—but not in this case. See, what Liberg actually wrote was this: “Most cats (80-85%) were house-based and obtained from 15 to 90% of their food from natural prey, depending on abundance and availability of the latter.” [7, emphasis mine] He was merely drawing the distinction between food provided by humans and any prey that cats might eat as food.

Liberg goes on to point out that the predation he documented did not, “justify a conclusive assessment of the effects of cats on their prey populations, but… indicate[s] that cats by themselves were not limiting any of their prey.” [7] Even high rates of predation do not equate to population declines.

“In California, 67 percent of rodents, 95 percent of birds, and 100 percent of lizards brought home by cats were native species, and native birds were twice as likely to be seen in areas without cats.”

What looks to be truly damning evidence loses much of its impact when it’s seen in context. The reference to Crooks and Soulé’s 1999 paper, for example, omitted the sample size involved: “Identification of 68 prey items returned by cats bordering the fragments indicated that 67% of 26 rodents, 95% of 21 birds and 100% of 11 lizards were native species.” [8] It’s important to note, too, that these researchers asked residents to recall what kind of prey their cats returned—no prey items were collected—thereby raising questions about the accuracy of species attribution.

Furthermore, the cats involved with Crooks and Soulé’s study were all pet cats. How their habits compare with those of feral cats is an open question. Merritt Clifton of Animal People, an independent newspaper dedicated to animal protection issues, suggests, “feral cats appear to hunt no more, and perhaps less, than free-roaming pet cats. This is because, like other wild predators, they hunt not for sport but for food, and hunting more prey than they can eat is a pointless waste of energy.”

The second portion of the quote refers to Cole Hawkins’ PhD dissertation. Hawkins’ research methods and analysis are so problematic that the suggestion of a causal relationship between the presence of cats and the absence of birds (native or otherwise) is highly inappropriate (indeed, Hawkins scarcely investigates predation at all).

Among the key issues: Hawkins had no idea what the “cat” area of his study site was like before the cats were there; he merely assumes it was identical to the “no cat” area in terms of its fauna (though the two landscapes are actually quite different). It’s also interesting to note Hawkins’ emphasis on “the preference of ground feeding birds for the no-cat treatment” while downplaying the fact that five of the nine ground-feeding species included in the study showed no preference for either area. (For a more comprehensive analysis, please see my previous post on the subject.)

“…cats are the most important species in the life cycle of the parasite responsible for toxoplasmosis, and in 3 separate studies, most feral cats (62 percent to 80 percent) tested positive for toxoplasmosis.”

While cats are the “definitive host,” it’s important to note that “wild game can be a source of T. gondii infection in humans, cats, and other carnivores. Serologic data show that a significant number of feral pigs, bears, and cervids are exposed to T. gondii.” [9]

“Humans,” write Elmore et al., “usually become infected through ingestion of oocyst-contaminated soil and water, tissue cysts in undercooked meat, or congenitally. Because of their fastidious nature, the passing of non-infective oocysts, and the short duration of oocyst shedding, direct contact with cats is not thought to be a primary risk for human infection.” [10]

Toxoplasma gondii has been linked to the illness and death of marine life, primarily sea otters [11], prompting investigation into the possible role of free-roaming (both owned and feral) cats. [12, 13] It’s generally thought that oocysts (the mature, infective form of the parasite) are transferred from soil contaminated with infected feces to coastal waterways by way of freshwater run-off. [13]

However, a 2005 study found that 36 of 50 sea otters from coastal California were infected with the Type X strain of T. gondii [14], a type linked to wild felids (mountain lions and a bobcat, in this case), but not to domestic cats. [13] A recently published study from Germany seems to corroborate these findings. Herrmann et al. analyzed 18,259 fecal samples (all from pet cats) for T. gondii and found no Type X strain. (It’s interesting to note, too, that only 0.25% of the samples tested positive for T. gondii). [15]

[NOTE: Please see follow-up post for additional information about cats and T. gondii.]

“Predation by cats on birds has an economic impact of more than $17 billion dollars [sic] per year in the U.S. The estimated cost per bird is $30, based on literature citing that bird watchers spend $0.40 per bird observed, hunters spend $216 per bird shot, and bird rearers spend $800 per bird released.”

According to this bizarre form of accounting, hunters value an individual bird more than 500 times as much as a birdwatcher does—suggesting, it seems, that dead birds are far more valuable than live birds. This is the kind of estimate that can be developed only through university (or perhaps government) research efforts.

Public Indecency
“Stephen Vantassel, a wildlife damage project coordinator who worked on the study, said researchers were aware that some people would be ‘very offended that we offered any type of lethal control method.’ But he said the report was written for public consumption and wasn’t submitted to any science journals for publication.” [1]

For the record, Dr. Vantassel, I’m more offended by the way you’ve allowed such sloppy, grossly irresponsible work to pass for “research.” And the idea that such an undertaking is somehow acceptable because it’s meant for a mass audience is simply absurd!

Naturally, the American Bird Conservancy (ABC) embraced the report immediately, “with one official calling it ‘a must read for any community or government official thinking about what to do about feral cats.’” [1]

“‘Not surprisingly, the report validates everything American Bird Conservancy has been saying about the feral cat issue for many years—namely, TNR doesn’t work in controlling feral cat populations,’ Darin Schroeder, vice president of the Conservation Advocacy for American Bird Conservancy, said Tuesday.”

But validation requires far more than this report provides—beginning with a real interest in scientific inquiry and some basic critical thinking skills. And while we’re at it, a refresher in ethics wouldn’t hurt, either.

* * *

In my previous post, I’d indicated that my next post—this post—was going to focus on The American Bird Conservancy Guide to Bird Conservation. Obviously, something came up. Anyhow, the book will keep for a few more days…

Literature Cited
1. n.a. (2010) Report: Kill feral cats to control their colonies. http://www.necn.com/11/30/10/Report-Kill-feral-cats-to-control-their-/landing_scitech.html?&blockID=3&apID=95afccc4d9564caf8e264f9d087f5732 Accessed December 1, 2010.

2. Hildreth, A.M., Vantassel, S.M., and Hygnstrom, S.E., Feral Cats and Their Managment. 2010, University of Nebraska-Lincoln Extension: Lincoln, NE. http://elkhorn.unl.edu/epublic/live/ec1781/build/ec1781.pdf

3. Fitzgerald, B.M. and Turner, D.C., Hunting Behaviour of domestic cats and their impact on prey populations, in The Domestic Cat: The biology of its behaviour, D.C. Turner and P.P.G. Bateson, Editors. 2000, Cambridge University Press: Cambridge, U.K.; New York. p. 151–175.

4. Mead, C.J., “Ringed birds killed by cats.” Mammal Review. 1982. 12(4): p. 183-186. http://dx.doi.org/10.1111/j.1365-2907.1982.tb00014.x

5. Leyhausen, P., Cat behavior: The predatory and social behavior of domestic and wild cats. Garland series in ethology. 1979, New York: Garland STPM Press.

6. Elliott, J. (1994, March 3–16). The Accused. The Sonoma County Independent, pp. 1, 10

7. Liberg, O., “Food Habits and Prey Impact by Feral and House-Based Domestic Cats in a Rural Area in Southern Sweden.” Journal of Mammalogy. 1984. 65(3): p. 424-432. http://www.jstor.org/stable/1381089

8. Crooks, K.R. and Soule, M.E., “Mesopredator release and avifaunal extinctions in a fragmented system.” Nature. 1999. 400(6744): p. 563.

9. Hill, D.E., Chirukandoth, S., and Dubey, J.P., “Biology and epidemiology of Toxoplasma gondii in man and animals.” Animal Health Research Reviews. 2005. 6(01): p. 41-61. http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=775956&fulltextType=RA&fileId=S1466252305000034

10. Elmore, S.A., et al., “Toxoplasma gondii: epidemiology, feline clinical aspects, and prevention.” Trends in Parasitology. 26(4): p. 190-196. http://www.sciencedirect.com/science/article/B6W7G-4YHFWNM-1/2/2a468a936eb06649fde0463deae4e92f

11. Jones, J.L. and Dubey, J.P., “Waterborne toxoplasmosis – Recent developments.” Experimental Parasitology. 124(1): p. 10-25. http://www.sciencedirect.com/science/article/B6WFH-4VXB8YT-2/2/8f9562f64497fe1a30513ba3f000c8dc

12. Dabritz, H.A., et al., “Outdoor fecal deposition by free-roaming cats and attitudes of cat owners and nonowners toward stray pets, wildlife, and water pollution.” Journal of the American Veterinary Medical Association. 2006. 229(1): p. 74-81. http://avmajournals.avma.org/doi/abs/10.2460/javma.229.1.74

13. Miller, M.A., et al., “Type X Toxoplasma gondii in a wild mussel and terrestrial carnivores from coastal California: New linkages between terrestrial mammals, runoff and toxoplasmosis of sea otters.” International Journal for Parasitology. 2008. 38(11): p. 1319-1328. http://www.sciencedirect.com/science/article/B6T7F-4RXJYTT-2/2/32d387fa3048882d7bd91083e7566117

14. Conrad, P.A., et al., “Transmission of Toxoplasma: Clues from the study of sea otters as sentinels of Toxoplasma gondii flow into the marine environment.” International Journal for Parasitology. 2005. 35(11-12): p. 1155-1168. http://www.sciencedirect.com/science/article/B6T7F-4GWC8KV-2/2/2845abdbb0fd82c37b952f18ce9d0a5f

15. Herrmann, D.C., et al., “Atypical Toxoplasma gondii genotypes identified in oocysts shed by cats in Germany.” International Journal for Parasitology. 2010. 40(3): p. 285–292. http://www.sciencedirect.com/science/article/B6T7F-4X1J771-2/2/dc32f5bba34a6cce28041d144acf1e7c

Garden Tool

12 Oct 2010•Cats and Birds, In the News

The timing was uncanny. Four days after my post “Inside Job,” Washington Post columnist Adrian Higgins reported incorrectly that two-thirds of pet cats are allowed outdoors. Higgins doesn’t mention where he got that figure, but considering the sources he used for the piece—including the American Bird Conservancy (ABC), The Wildlife Society, and Dauphiné and Cooper’s 2009 Partners in Flight paper—it’s not hard to sort out.

Ditto for his matter-of-fact assertion that “the cumulative effect on birds is significant, according to experts.” Higgins relies on Dauphiné and Cooper for estimates of both the number of “stray and out-and-out feral cats” (“there may be as many as 100 million such cats in the country”) and birds killed by free-roaming cats (“at least one billion birds are killed by cats annually, ‘and the actual number is probably much higher.’”). [1]

Higgins’ column appeared exactly one week after the release of Charles Seife’s book Proofiness: The Dark Arts of Mathematical Deception. Proofiness, writes Seife, is “the art of using bogus mathematical arguments to prove something that you know in your heart is true—even when it’s not.” [2]

Many—perhaps most—of the scientific claims made by opponents of free-roaming cats/TNR are textbook cases of proofiness. Nevertheless, they are often accepted at face value by the media, which—simply by passing them along for public consumption—gives these assertions unwarranted credibility.

Pete Marra
The central character in Higgins’ story is Pete Marra, a fellow gardener and a research associate at the Smithsonian Conservation Biology Institute. Marra’s name rang a bell.

Sure enough, this is the same Peter P. Marra who, along with nine others (including Dauphiné and Cooper), authored a comment in Conservation Biology earlier this year, entitled “What Conservation Biologists Can Do to Counter Trap-Neuter-Return: Response to Longcore et al.” (the publication of which prompted a series of Vox Felina posts, beginning with this one).

What Marra and his co-authors penned is an unapologetic call to action:

Proponents of TNR are well organized and push for TNR-friendly policies in communities and shelters around the United States, often with little opposition from the conservation biology and wildlife ecology communities… Regardless of why the scientific and management communities have remained relatively silent, it is imperative that we now begin speaking out. [2]

As I have argued, the silence that so frustrates Marra and the others may simply reflect the fact that so much of the work he and his colleagues defend is largely indefensible. Indeed, “What Conservation Biologists Can Do” is, in its own way, representative. Consider the authors’ comparison of TNR with hoarding:

The animal welfare community opposes “cat hoarding,” whereby people care for more pets than they can adequately support, because it is considered inhumane. Trap-neuter-return is essentially cat hoarding without walls. Considering that most communities have laws banning animal hoarding, we should consider the same standard for outdoor cats as those that are in a person’s home. [3]

But their interest in using the law to put a stop to TNR doesn’t end there. Marra and his colleagues continue:

…it may become incumbent upon us to take legal action against colonies and colony managers, particularly in areas that provide habitat for migratory birds or endangered species. [3]

The authors quote a 2003 article written by Linda Winter, the former director of the ABC’s Cats Indoors! campaign, for the Hawaii Audubon Society newsletter:

“…releasing cats into the wild and supporting feral cat colonies is a violation of the Migratory Bird Treaty Act and the Endangered Species Act, as well as laws prohibiting animal abandonment.” (her emphasis, not mine) [4]

As a frequent critic of Winter’s writing, I was eager to read the newsletter (which can be downloaded here). It turns out Winter was referring to a 2003 report submitted by Pamela Jo Hatley—then a student in the University of Florida’s Levin College of Law and part of its University of Florida Conservation Clinic—to the U.S. Fish & Wildlife Service.

Winter—and by extension, Marra and his colleagues—are unambiguous on this point: TNR is a clear violation of both the Migratory Bird Treaty Act and the Endangered Species Act. But, of course, law students don’t make legal decisions; that’s what we have courts for (which might explain why, years later, Travis Longcore and his Urban Wildlands Group took a rather different approach in their TNR-related lawsuit against the City of Los Angeles).

But back to Hatley—there’s another familiar name. In fact, I’d seen it right beside Marra’s earlier this year. See, Pamela Jo Hatley is one of the 10 co-authors of “What Conservation Biologists Can Do.”

So why didn’t the authors just cite Hatley’s work directly, rather than turning to Winter’s version of it? Simply put, Winter’s version is a better story—short and sweet, and brimming with certitude.

But if Marra and the others—Hatley included—wanted to distance themselves from the original, it’s understandable. Though her legal arguments are somewhat compelling, Hatley’s report is a minefield of misrepresentations, flawed estimates, and unsubstantiated claims where the science is concerned (e.g., extrapolating the Wisconsin Study to Florida, and then suggesting that “the actual number [of birds killed by cats in the state] may be much higher” [5]). In other words, more proofiness.

Its title, Feral Cat Colonies in Florida: The Fur and the Feathers Are Flying, is a good indication of how seriously the report—ostensibly a formal document submitted to a federal agency—should be taken.

Getting Dirty
To read Higgins’ column in the Post, one gets the idea that he and Marra are merely fellow gardeners, perhaps having bumped into each other at the local nursery or hardware store. And that’s where the story began. It could be.

But there’s a sentence in “What Conservation Biologists Can Do” that’s been bothering me ever since I read Higgins’ piece:

Conservation biologists have just as much opportunity to make their points at local meetings, through the news media, and at outreach events as do TNR proponents. (emphasis mine) [2]

I have no idea whether Higgins and Marra knew each other before Higgins began work on his column, or how Higgins feels about cats. And I’m not one to go in for conspiracy theories, either.

What I am sure of is that Higgins—as a journalist—should have done his homework. He did not. (To be fair, Higgins did speak with Alley Cat Allies; but “equal time” is a poor substitute for accuracy.) And the consequences of his carelessly scattering a few figures around a column devoted to gardening are considerable: the seeds of proofiness!

Maybe readers don’t expect Higgins to know (or care, even) how many free-roaming cats there are in the U.S. Or how much time pet cats spend outdoors. Still, though, Higgins is an avid gardener—he, of all people, should be able to recognize bullshit.

* * *

SPECIAL THANKS to Louise Holton, founder of Alley Cat Rescue, who brought the Washington Post article (along with countless other news items over the past few months!) to my attention. She and Maggie Funkhouser, ACR’s Director of Communications and Public Relations, have become invaluable resources.

Literature Cited
1. Higgins, A., Bird lovers see roaming cats as a major threat to many species, in The Washington Post. 2010: Washington, DC. http://www.washingtonpost.com/wp-dyn/content/article/2010/09/28/AR2010092803999.html

2. Seife, C., Proofiness: The Dark Arts of Mathematical Deception. 2010: Viking Adult.

3. Lepczyk, C.A., et al., “What Conservation Biologists Can Do to Counter Trap-Neuter-Return: Response to Longcore et al.” Conservation Biology. 2010. 24(2): p. 627-629.

4. Winter, L., “Popoki and Hawai’i’s Native Birds.” ‘Elepaio: Journal of the Hawaii Audubon Society. 2003. 63(6).

5. Hatley, P.J., Feral Cat Colonies in Florida: The Fur and the Feathers Are Flying. 2003, University of Florida Conservation Clinic: Gainsville, FL.

False Confessions

12 Aug 2010•Animal Hoarding, In the News

Whether the latest iteration of reality TV— Animal Planet’s Confessions: Animal Hoarding—is more education, entertainment, or exploitation is a matter of debate. But it’s a safe bet that by streaming “an unflinchingly honest look at a human condition that affects people and animals” into living rooms across the country, a problem too rarely acknowledged (not to mention taken seriously) is now receiving unprecedented attention.

Even if I were a cable subscriber, though, I don’t think I’d be tuning in. Although I was nowhere near the “front lines” of the Great Kitty Rescue, I’ve seen and heard plenty where animal hoarding is concerned. But in reading about Confessions, I was reminded of some remarks included in a comment published earlier this year in Conservation Biology. There, Christopher Lepczyk, Nico Dauphiné, David M. Bird, Sheila Conant, Robert J. Cooper, David C. Duffy, Pamela Jo Hatley, Peter P. Marra, Elizabeth Stone, and Stanley A. Temple compared TNR to animal hoarding:

“The animal welfare community opposes ‘cat hoarding,’ whereby people care for more pets than they can adequately support, because it is considered inhumane. Trap-neuter-return is essentially cat hoarding without walls. Considering that most communities have laws banning animal hoarding, we should consider the same standard for outdoor cats as those that are in a person’s home.” [1]

This strikes me as almost desperate—the latest volley in the kitchen-sink/something-for-everybody approach taken by some TNR opponents. Nevertheless, the analogy—however incongruous—is not new. In 2004, David Jessup made essentially the same comparison:

“Some people are compelled to own and care for excessive numbers of cats. This psychological illness is referred to as ‘collectors psychosis.’ How is the person who must save 25 to 30 cats in their home different from the person who sees themselves [sic] as the savior of 25 to 30 cats in a park? Some ‘cat people’ may be ‘collectors,’ and it is possible that TNR is enabling and supporting some people who need psychologic counseling and assistance.” [2]

Jessup doesn’t burden himself or his audience with even the slightest support for his assertions; his claims are as much conjecture as anything else, his question largely rhetorical. Five years later, Dauphiné and Cooper revisited Jessup’s query, but—despite a handful of references—do no better in terms of its resolution:

“In many cases, the characteristics and behavior of people involved in TNR are suggestive of the psychiatric disorders described in problematic animal hoarding [3]. When presented with alternatives to TNR, such as enclosed sanctuaries, no-kill shelters, and traditional animal control, many such people can be “fiercely protective, retaliatory, and uncooperative,” [4] and will subject public officials and other citizens opposing TNR to harassment and threats [5, 6].” [7]

Animal Hoarding
Dauphiné and Cooper’s argument presupposes that enough is known both about “people involved in TNR” and “the psychiatric disorders described in problematic animal hoarding” for a valid comparison to be made. In fact, very little is known about either one. Randy Frost, whose 2000 article the authors cite, begins by noting, “almost no psychiatric literature exists on this topic.” [3] A year earlier, Gary Patronek (a collaborator of Frost’s, whose work Frost cites throughout his paper) observed: “Unlike the hoarding of inanimate objects, which may be linked with a variety of psychiatric conditions, animal hoarding has not yet been linked with any specific disorder.” [8]

Nevertheless, both Patronek and Frost describe—based on some of the earliest research on the subject—some common characteristics of, and explanatory models for animal hoarding. And provide this definition:

“someone who accumulates a large number of animals; fails to provide minimal standards of nutrition, sanitation and veterinary care; and fails to act on the deteriorating condition of the animals (including disease, starvation and even death) or the environment (severe overcrowding, extremely unsanitary conditions), or the negative effect of the collection on their own health and well-being and on that of other household members.” [8]

This seems to have been the framework for the definition adopted by the Hoarding of Animals Research Consortium (with which Patronek and Frost were involved), which places greater emphasis on two key elements: denial, and accumulation and control:

Having more than the typical number of companion animals;
Failing to provide even minimal standards of nutrition, sanitation, shelter, and veterinary care, with this neglect often resulting in illness and death from starvation, spread of infectious disease, and untreated injury or medical condition;
Denial of the inability to provide this minimum care and the impact of that failure on the animals, the household, and human occupants of the dwelling;
Persistence, despite this failure, in accumulating and controlling animals.

“Saving” 25 or 30 cats, then—whether in one’s home or in the park—does not constitute animal hoarding. As Patronek pointed out during a recent interview on NPR’s Radio Times, “numbers alone don’t define hoarding… you’ve got to have these functional deficits and denial, in combination with the numbers.”

Opponents of TNR (and of free-roaming cats in general) will likely seize upon that second point, arguing that feral cat colonies—by definition—lack adequate care. But the very fact that these cats are part of a TNR program means they’ve been evaluated by veterinary professionals, requiring a concerted effort—sometimes bordering on the heroic—on the part of the trappers and caregivers involved. Some programs perform vaccinations (that this is not standard practice, is, admittedly, a controversial issue); at a minimum, cats deemed too sick to be returned are euthanized.

A 1999 survey of survey of “101 individuals or couples who cared for 132 colonies of free-roaming cats in north central Florida” illustrates the importance caregivers place on health:

“More than a third of the caretakers reported that they had provided some kind of veterinary care (not including being neutered at the TNR clinic) for the cats in the past or would provide veterinary care if it was necessary in the future. This type of care included booster vaccinations, parasite control, antibiotic treatment, ear medication, veterinary examinations, and emergency treatment.” [9]

In addition, 96% provided food, and 75% provided shelter. It’s important to note, too, that these numbers are conservative relative to the care received by the cats, in that (1) some caregivers were responsible for multiple cats, and (2) respondents to the survey were not necessarily the individuals who provided food, shelter, and so forth.

Such findings are certainly consistent with my own experience. The TNR networks I’m tapped into (mostly by way of e-mail or online bulletin boards) are typically buzzing with requests from, and recommendations to, caregivers committed to maintaining and improving the health of feral cat colonies.

On the other hand, it’s not clear from Dauphiné and Cooper’s paper that their reference to animal hoarding has anything to do with the behavior’s defining characteristics at all. More than anything else, the authors seem to be suggesting that resistance to TNR “alternatives” constitutes some psychiatric disorder—a possible reference to animal hoarders’ “reluctance to remove any animals, even when adequate homes were available.” [3]

Alternatives to TNR
Respectable sanctuaries, as I’ve already discussed, are few and far between, and typically at operating at capacity. In any case, such environments are not in the best interest of unsocialized cats. No-kill shelters, too, are scarce, and—recognizing realities Dauphiné and Cooper (and veterinarian Christine Storts, whose letter they cite) overlook or ignore—generally endorse TNR as their feral cat management approach. [10]

And as for “traditional animal control,” that’s nothing more than a rather cowardly euphemism for trap-and-kill.

What about the harassment and threats? Here, Dauphiné and Cooper cite Paul Barrows’ 2004 article “Professional, Ethical, and Legal Dilemmas of Trap-Neuter-Release,” and Pamela Jo Hatley’s 2004 paper, “Will Feral Cats Silence Spring in Your Town?” “During the past several years,” writes Barrows:

“as debate regarding abandoned and feral cats has become more heated, concerns have emerged regarding the extent to which some activists will go to promote their cause. Those supporting trap and removal of abandoned and feral cats, rather than TNR, have reported verbal abuse, personal threats, disruption of public forums, and interference with the conduction of their businesses.” [5]

Dauphiné and Cooper buy into Barrows’ account without bothering to check out his source (actually, these two make a shameful habit of such shortcuts throughout their paper, thereby raising questions about their numerous assertions, and, more problematically, their capabilities and integrity as researchers). In fact, Barrows cites a 2002 Wall Street Journal story in which exactly one of “those supporting trap and removal”—Frank Spiecker, of Garden State Pest Management—was interviewed:

“…property managers, fearing health complaints or lawsuits, hire Mr. Spiecker to trap and remove stray cats… Cat jobs have gotten him screamed at, threatened and jostled. His truck has been jumped on and pounded, his traps run over, and his trapped cats freed… To cat lovers, he abets feline mass murder, since most of the cats he traps end up dead.” [11]

All of which seems remarkably flimsy for describing and condemning—as Dauphiné and Cooper do—the behaviors of “many such people.” Until it’s compared to the even flimsier “evidence” provided by Hatley:

“Many citizens and public officials have voiced concerns about the public health issues and wildlife issues involved in hoarding large numbers of cats in the wild. Some who have resisted the extreme efforts by proponents of TNR and cat colonies have been subjected to verbal abuse and threats.” [6]

Dodgy research practices aside, the notion that one’s preference for TNR over “enclosed sanctuaries, no-kill shelters, and traditional animal control” is indicative of some psychiatric disorder remains a mighty hard sell. Dauphiné and Cooper’s so-called alternatives are simply not—in a very literal sense—viable options.

* * *

To compare TNR to animal hoarding betrays either a profound lack of knowledge about either one, or a desperate attempt to taint the former by association with the latter. I suspect that, like the most despicable political strategists, Jessup, Dauphiné and Cooper, and Lepczyk et al., threw it out there just to see if it would stick—the connection they’re attempting to make certainly has nothing to do with science.

I’ve a friend who jokes that the only thing feral cats aren’t being blamed for these days is climate change. Well, not yet, anyhow.

Literature Cited
1. Lepczyk, C.A., et al., “What Conservation Biologists Can Do to Counter Trap-Neuter-Return: Response to Longcore et al.” Conservation Biology. 2010. 24(2): p. 627-629.

2. Jessup, D.A., “The welfare of feral cats and wildlife.” Journal of the American Veterinary Medical Association. 2004. 225(9): p. 1377-1383.

3. Frost, R., “People Who Hoard Animals.” Psychiatric Times. 2000. 17(4).

4. Storts, C.M., “Discussion on TNR programs continue (letter).” Journal of the American Veterinary Medical Association. 2003. 222: p. 711–712.

5. Barrows, P.L., “Professional, ethical, and legal dilemmas of trap-neuter-release.” Journal of the American Veterinary Medical Association. 2004. 225(9): p. 1365-1369.

6. Hatley, P.J. (2004) Will Feral Cats Silence Spring in Your Town? www.pamelajohatley.com/Articles/ABA.pdf Accessed August 8, 2010.

7. Dauphiné, N. and Cooper, R.J., Impacts of Free-ranging Domestic Cats (Felis catus) on birds in the United States: A review of recent research with conservation and management recommendations, in Fourth International Partners in Flight Conference: Tundra to Tropics. 2009. p. 205–219.

8. Patronek, G.J., “Hoarding of animals: An under-recognized public health problem in a difficult-to-study population.” Public Health Reports. 1999. 114(1): p. 81–87.

9. Centonze, L.A. and Levy, J.K., “Characteristics of free-roaming cats and their caretakers.” Journal of the American Veterinary Medical Association. 2002. 220(11): p. 1627-1633.

10. Winograd, N.J., Redemption: The myth of pet overpopulation and the no kill revolution in America. 2007: Almaden Books.

11. Sterba, J.P., Tooth and Claw: Kill Kitty?, in Wall Street Journal. 2002: New York. p. A.1

The Work Speaks—Part 7: Leaky Sink

21 Jun 2010•Cats and Birds, Population Estimates, Research Protocol, Threats to Wildlife

In April, Conservation Biology published a comment authored by Christopher A. Lepczyk, Nico Dauphiné, David M. Bird, Sheila Conant, Robert J. Cooper, David C. Duffy, Pamela Jo Hatley, Peter P. Marra, Elizabeth Stone, and Stanley A. Temple. In it, the authors “applaud the recent essay by Longcore et al. (2009) in raising the awareness about trap-neuter-return (TNR) to the conservation community,” [1] and puzzle at the lack of TNR opposition among the larger scientific community:

“…it may be that conservation biologists and wildlife ecologists believe the issue of feral cats has already been studied enough and that the work speaks for itself, suggesting that no further research is needed.”

In fact, “the work”—taken as a whole—is neither as rigorous nor as conclusive as Lepczyk et al. suggest. And far too much of it is plagued by exaggeration, misrepresentations, errors, and obvious bias. In Part 6 of this series, I critiqued Christopher Lepczyk’s paper Landowners and cat predation across rural-to-urban landscapes, published in 2003. Here, I’m going to examine two studies conducted by Philip J. Baker and various collaborators.

The Studies
In the first study, Baker et al. distributed questionnaires to 3,494 households across a 4.2 km² area of northwest Bristol (UK), and used responses to estimate cat ownership and predation levels (via prey returned home). [2] This work served as a pilot study for the subsequent study.

The second study, conducted August 2005–July 2006, was also conducted in Bristol. Added to the original 4.2 km² site were nine 1 km² sites. The researchers used very similar sampling methods, but, based on results of their pilot study, had somewhat more specific objectives:

To quantify cat density
To quantify the various species of birds killed by cats.
To estimate the impact of cat predation by species and site.
To determine whether the predation observed was compensatory or additive. [3]

Sources and Sinks
Among the authors’ conclusions from the pilot study was that, at least for three of the ten bird species surveyed:

“…it is possible that cat predation was significantly affecting levels of recruitment and creating a dispersal sink for more productive neighboring areas.” [2]

Dispersal sinks or habitat sinks, are patches of low-quality habitat that are unable to sustain a population of a particular species were it not for immigration from higher quality habitat patches—called sources—nearby. So, what Baker et al. are suggesting is that predation by cats may be extensive enough to deplete populations of certain bird species at their study site, such that at least some of the birds observed there were immigrants from nearby habitat.

But the authors also point out that, “despite occurring at very high densities, the summed effects on prey populations appeared unlikely to affect population size for the majority of prey species.” [2] And even for House sparrows, which were among the three species of concern (and, apparently, in decline throughout the UK’s urban areas), Baker et al. note that their “numbers appear to be stable in Bristol as a whole.”

So, is the area a habitat sink or not?

A cursory look at the theory and empirical measurement of source-sink dynamics reveals great complexity. Variations across time and geography must be taken into account—the ebb and flow of local populations might easily be overlooked or misunderstood by applying a short time horizon (i.e., 12 months) and arbitrary boundaries (i.e., those that define the study site). Annual rainfall, for example, can dramatically influence yearly population levels on a local scale. And it’s been shown that source-sink dynamics can occur over distances of 60–80 km. [4] In fact, the determination of sinks and sources in the field can be problematic enough that sources sometimes appear to be sinks and vice-versa. [5]

Given the complex nature of source-sink dynamics, the suggestion by Baker et al. that cat predation may be creating a habitat sink seems rather premature. Such assertions—despite the requisite disclaimers (the authors note only that “it is possible”)—tend to attract attention and gain traction. Longcore et al., for example, cited the pilot study in their 2009 essay, “Critical Assessment of Claims Regarding Management of Feral Cats by Trap-Neuter-Return.” [6]

Of greater interest to me, though, are the assumptions Baker et al. used to estimate the impact of cat predation.

Counting Cats and Counting Birds
In both studies, the authors quantified the impact of cat predation on bird populations by comparing different levels of predation with different bird densities. Their maximum impacts, for example, assumed that all cats were hunters—despite the fact that 51–74% of the cats included in the two studies brought home no prey at all—and that bird productivity was zero (i.e., no young birds survive to adulthood). As the authors admit:

“This was clearly not realistic, as the estimated maximum numbers of birds killed typically exceeded breeding density and productivity combined, such that the prey populations studied would probably have gone extinct rapidly at a local level or acted as a major sink for birds immigrating from neighbouring areas.” [3]

But how realistic are their other estimates?

A detailed examination of a single species at a one site (taken from the second study, for which such information is available) illustrates some flaws. I looked at House sparrows for the 1 km² site designated as ST5277. Here, 18 participants reported that their 22 cats returned a total of 30 prey items, nine of which were birds (two of them “unidentified”). Of the birds returned home, two were House sparrows.

When it comes to estimating impacts, though, Baker et al. use figures of 332–1,245 House sparrows killed by the cats of ST5277. The maximum, we already know, is “not realistic,” but even the minimum seems awfully high. So, where are these birds coming from?

To start with, two adjustments have to be made to the original predation figure. First, the two unidentified birds are “distributed” across the categories of bird species that were identified. Then, we have to account for participant drop-out; not all of the 22 cats were surveyed for the entire year of the study. Now we’re up to an average of 8.7 House sparrows brought home annually by the cats at this site.

But of course there are more than 22 cats at ST5277. Baker et al. estimate that there are 314 of them (although we know very little about the factors that affect their hunting ability and success—for example, their access to the outdoors, age, etc.). We also know that only seven of the 22 cats included in the study brought home prey. In other words, 32% of the cats surveyed were documented hunters. Based on these numbers, then, we can estimate the yearly predation rate of House sparrows at ST5277 to be roughly 125—well short of the minimum proposed by Baker et al. (and just a quarter of their intermediate rate).

There are some minor differences between their method for estimating predation rates and mine. For the most part, though, the “missing” sparrows can be found in the authors’ use of a correction factor (3.3) proposed by Kays and DeWan to account for prey killed but not returned home. [7] Undoubtedly, cats fail to bring home all the prey they catch (though they also undoubtedly bring home prey they didn’t kill), but there is good reason to doubt Kays and DeWan’s “correction.” Among the flaws in their analysis were small, dissimilar samples of cats, and a failure to account for highly skewed data sets.

So, even setting aside the complexities of source-sink dynamics, these inflated predation rates, combined with the fact that “the estimates of breeding density presented in this manuscript should be regarded as minima,” [3] raise serious doubts about whether the site is in fact a habitat sink (or, if so, to what extent).

Compensatory and Additive Predation
As I’ve discussed previously, even accurately predicted levels of predation can be deceptive. There’s compensatory predation (in which prey would have died even in the absence of a particular predator, due to illness, starvation, other predators, etc.) and additive predation (in which healthy prey are killed). It’s the difference between, as Beckerman et al. put it, the “doomed surplus hypothesis” and the “hapless survivor hypothesis.” [8]

When it comes to relating predation to population levels, it’s critical to understand the difference, and know the extent to which each type is occurring.

To get at this critical issue, Baker et al. compared the physical attributes (e.g., muscle mass score, mean fat score, etc.) of 86 birds killed by collisions (e.g., with cars, windows, etc.) to those of 48 birds killed by cats. Although the authors point out, “the relationship between body mass and quality (i.e., likelihood of long-term survival and therefore reproductive potential) in passerines is complex,” they nevertheless conclude that the birds killed by cats “were likely to have had poor long-term survival prospects.” [3] (An earlier study comparing spleen mass arrived at essentially the same conclusion: that birds killed by cats “often have a poor health status.” [9])

Still, Baker et al. express caution about their findings:

“The distinction between compensatory and additive mortality does, however, become increasingly redundant as the number of birds killed in a given area increases: where large numbers of prey are killed, predators would probably be killing a combination of individuals with poor and good long-term survival chances. The predation rates estimated in this study would suggest that this was likely to have been the case for some species on some sites.”

But their inflated predation rates and low estimates of breeding density combine to diminish the apparent level of compensatory predation. Were these estimates adjusted to better reflect the conditions at the site, the “redundancy” the authors refer to would be reduced considerably.

* * *

It’s not clear why Longcore et al. cited the pilot study their essay, but left out any mention of the much larger subsequent study. Perhaps it was just a matter of timing—“Cats About Town” was published in August of 2008, while “Critical Assessment” was published in August of 2009. A year is not much time in the world of scientific journals, and it’s possible that the two manuscripts more or less crossed in the mail. On the other hand, the pilot study fits more neatly into the argument put forward by Longcore et al.—an argument that doesn’t even recognize the distinction between compensatory and additive predation.

Of course, Baker et al. did themselves no favors, either. By using inflated predation rates—the result of some peculiar, unjustified assumptions—they virtually buried the most important findings of their study.

References
1. Lepczyk, C.A., Mertig, A.G., and Liu, J., “Landowners and cat predation across rural-to-urban landscapes.” Biological Conservation. 2003. 115(2): p. 191-201.

2. Baker, P.J., et al., “Impact of predation by domestic cats Felis catus in an urban area.” Mammal Review. 2005. 35(3/4): p. 302-312.

3. Baker, P.J., et al., “Cats about town: is predation by free-ranging pet cats Felis catus likely to affect urban bird populations?“ Ibis. 2008. 150: p. 86-99.

4. Tittler, R., Fahrig, L., and Villard, M.-A., “Evidence of Large-Scale Source-Sink Dynamics and Long-Distance Dispersal among Wood Thrush Populations.” Ecology. 2006. 87(12): p. 3029-3036.

5. Runge, J.P., Runge, M.C., and Nichols, J.D., “The Role of Local Populations within a Landscape Context: Defining and Classifying Sources and Sinks.” The American Naturalist. 2006. 167(6): p. 925-938.

6. Longcore, T., Rich, C., and Sullivan, L.M., “Critical Assessment of Claims Regarding Management of Feral Cats by Trap–Neuter–Return.” Conservation Biology. 2009. 23(4): p. 887–894.

7. Kays, R.W. and DeWan, A.A., “Ecological impact of inside/outside house cats around a suburban nature preserve.” Animal Conservation. 2004. 7(3): p. 273-283.

8. Beckerman, A.P., Boots, M., and Gaston, K.J., “Urban bird declines and the fear of cats.” Animal Conservation. 2007. 10(3): p. 320-325.

9. Møller, A.P. and Erritzøe, J., “Predation against birds with low immunocompetence.” Oecologia. 2000. 122(4): p. 500-504.

The Work Speaks—Part 6: Pain by Numbers

14 Jun 2010•Cats and Birds, Population Estimates, Research Protocol, The Cat Debate, Threats to Wildlife

“…it may be that conservation biologists and wildlife ecologists believe the issue of feral cats has already been studied enough and that the work speaks for itself, suggesting that no further research is needed.”

In fact, “the work”—taken as a whole—is neither as rigorous nor as conclusive as Lepczyk et al. suggest. And far too much of it is plagued by exaggeration, misrepresentations, errors, and obvious bias. In Part 5 of this series, I critiqued Cole Hawkins’ 1998 PhD dissertation. Here, I’m going to untangle some of Lepczyk’s own PhD work: Landowners and cat predation across rural-to-urban landscapes, published in 2003.

The Study
In this study, surveys were distributed across three southeastern Michigan landscapes (rural, suburban, and urban) corresponding to established breeding bird survey (BBS) routes. [2] Among the survey questions:

“If you or members of your household own cats that are allowed access to the outside, approximately how many dead or injured birds a week do all the cats bring in during the spring and summer months (April through August) (0, 1, 2–3, 4–5, 6–7, 8–9, 10–15, 16–20, more than 20)?”

Based on 968 surveys returned from 1654 private landowners (a decent response rate of 58.5%), Lepczyk et al. conclude:

“Across the three landscapes there were ~800 to ~3100 cats, which kill between ~16,000 and ~47,000 birds during the breeding season, resulting in a minimum of ~1 bird killed/km/day.”

Increasing Uncertainty
How do Lepczyk and his collaborators arrive at these figures? It’s not entirely clear, actually. Despite numerous attempts, I’ve been unable to follow all of their calculations. However, using their data, I developed my own estimate: 1,119 outdoor cats, 511 of which were reported to be successful hunters.

Using this figure, I then summed across all three landscapes the birds killed or injured, plus those killed or injured by non-respondents’ hunting cats (based on the ratio of hunters to outdoor cats owned by respondents, or about 50%). The resulting estimate is 15,856 birds killed over the 22-week breeding season—close to the low estimate suggested by Lepczyk et al., but just a third of their maximum.

So, why the discrepancy?

One reason is that, at least for some of their estimates, Lepczyk et al. assumed that every landowner who didn’t respond to the survey owned outdoor cats. This, despite their survey results, which indicated that only about one-third of landowners fell into this category.

But the authors go further, generating predation estimates based on pure speculation, specifically that “non-respondents have 150% the number of outdoor cats as respondents.” [2] It should be noted that Lepczyk et al. also ran another scenario in which non-respondents had half the outdoor cats as did respondents—but, again, in both cases they assume that every non-respondent owned outdoor cats.

As a result of this approach, the authors end up in some strange territory: the estimated number of cats owned by non-respondents (based on the assumptions described above) far exceeds the number owned by respondents—by more than a two-to-one margin, in some cases. If the greatest impacts are going to be attributable to non-respondents, then what’s the point of doing the survey in the first place? There are accepted methods by which one can manage uncertainty—statistical analysis, confidence intervals, and the like. What Lepczyk et al. have done serves just one purpose: to inflate apparent predation rates.

Skewed Distributions
In addition to the flaws described above, there are some fundamental errors in the way the authors handle their data. Like so many others, Lepczyk et al. ignore the fact that their data is not normally distributed:

Lepczyk et al. use the average number of birds killed/cat to calculate the total number of bids killed for each of the three landscapes. As I discussed previously), this is a highly positively skewed distribution—using a simple average, therefore, greatly overestimates the cats’ impact (by as much as a factor of two).
A similar error is made when the authors use an average to describe the number of outdoor cats owned by each landowner. Again, because this is a skewed distribution, their use of a simple average exaggerates the extent of predation.
The two inflated figures described in (1) and (2) are multiplied together, further inflating estimated predation rates.

Barratt has suggested that “median numbers of prey estimated or observed to be caught per year are approximately half the mean values, and are a better representation of the average predation by house cats based on these data.” [3] Accounting for the first point alone, then, my estimate is reduced to 8,000 birds killed over the 22-week breeding season.

Accounting for the second point is somewhat trickier. For one thing, we don’t know what constitutes an outdoor cat here—the survey simply asked respondents if they owned cats “that are allowed access to the outdoors.” [2] However, we do know the results of a 2003 survey, which indicated that nearly half of the cats with outdoor access were outside for two or fewer hours a day. And 29% were outdoors for less than an hour each day. [4] Although these figures almost certainly reflect owners in urban and suburban landscapes more than those in rural landscapes, it’s clear that a simple yes-or-no question on the subject is insufficient. Indeed, such a question will invariably overestimate the number of “outdoor cats”—which in turn overestimates predation rates.

This, coupled with the error inherent in using a simple average, pushes predation estimates lower. And the third point reduces those estimates further still. Taken together, these corrections could put my estimate closer to 4,000 birds. More important, the upper estimate proposed by Lepczyk et al.—47,000 birds—could easily be 10 times too high.

The Small Print
Despite their inflated figures, Lepczyk et al. suggest—rather absurdly, in light of the substantial flaws described above—that perhaps their estimates are actually too conservative:

“One caveat to our study is that landowners may have underestimated the number of cats they allow access to the outside. Such a result was found in a similar study of landowners in Wisconsin (Coleman and Temple, 1993).” [1] (Note: After reviewing “Rural Residents’ Free-Ranging Domestic Cats: A Survey,” [5] I’ve found no evidence of such a result.)

“… we found that a very common volunteered response among landowners that had no outdoor cats was that either their neighbors owned outdoor cats or that feral cats were present in the vicinity of their land… [suggesting] that at least some landowners under reported or chose not to report the number of outdoor cats they owned.”

But what about their reports of birds brought home killed or injured—how trustworthy were those? After all, the survey (mailed during the first week of October) asked respondents to recall the number of birds their cat(s) brought home April through August. Surely, there was a lot of guesswork involved. In fact, David Barratt found this kind of guesswork to overestimate predation rates. In a study published five years prior to “Landowners and Cat Predation,” Barratt concluded, “predicted rates of predation greater than about ten prey per year generally over-estimated predation observed.” [3]

The two studies cannot be compared directly for a number of reasons, but by way of comparison, the average predation rate used by Lepczyk et al. is approximately 31 birds/cat for the 22-week breeding season. Using Barratt’s work, in which the “heaviest” six continuous months correspond to about 58% of yearly prey totals, [6] I converted this to a yearly rate of 53 birds/cat/year. Barratt has shown that the actual predation rate, at this level, is less than half the rate predicted by cat owners. In other words, predictions of 50 birds/year generally correspond to catches closer to 25 birds/year.

While Lepczyk et al. emphasize the potential for under-estimating predation levels, they never consider the risk of over-estimating these levels—or their most obvious potential source of error: landowners’ recollections of birds killed. The authors question respondents’ reports of outdoor cats, but accept without question their reports of birds injured or killed over the previous six-month period. And, as Barratt indicated, such reports can be inflated by a factor of two or more!

Something else I find troubling comes, of all places, from the Acknowledgements section. Among those thanked “for helpful and constructive reviews” are American Bird Conservancy (ABC) president George Fenwick and Linda Winter, director of ABC’s Cats Indoors! campaign. It’s not clear how Fenwick and Winter contributed to the final paper, but their involvement on any level raises questions about possible bias. Certainly, Winter has credibility issues when it comes to “research” about the impact of free-roaming cats on birds, as I’ve already described (see also pp. 18–24 of TNR Past present and future: A history of the trap-neuter-return movement [7]).

* * *

The same year Lepczyk’s paper was published, the American Veterinary Medicine Association held an Animal Welfare Forum “devoted to the management of abandoned and feral cats.” [8] In attendance were more than 200 veterinarians, animal control officials, wildlife conservationists, and animal advocates—each with a different perspective on feral cats in general and TNR in particular.

In welcoming this diverse group, then-President-Elect Bonnie Beaver recognized the range of contentious issues before them:

“Feral cats evoke hot debates about ecological issues, individual cat welfare, human responsibilities, intercat disease transmission, humaneness, zoonosis control, and management and dissolution of unowned cats.” [8]

Amidst the “hot debate,” though, Beaver was optimistic:

“We will not always agree, but we will come away with increased knowledge and a renewed commitment to work for the welfare of all the animals with which we share the earth” [8]

While I tend to share Beaver’s optimism, I think the debate is hurt—if not derailed entirely—by the publication of research aimed not at increasing our collective knowledge, but rather at supporting a particular position. Like Cole Hawkins’ dissertation, “Landowners and Cat Predation” is, at best, an interesting pilot study for subsequent work. And yet, it’s widely—and uncritically—cited in the feral cat/TNR literature. Longcore et al., for example, refer to it as “evidence [indicating] that cats can play an important role in fluctuations of bird populations,” [9] despite the fact that Lepczyk et al. don’t actually address the issue of bird populations at all. More recently, Dauphiné and Cooper use the inflated predation rate suggested by Lepczyk et al. (along with rates proposed by other researchers) to arrive at their “billion birds” figure. [10]

The method employed in “Landowners and Cat Predation”—asking owners of cats to recall the number and species of birds over the previous six-month period—invites overestimation from the very outset. Lepczyk et al. then inflate these numbers through both careless (e.g., using averages to describe skewed data) and deliberate (e.g., assuming all non-respondents owned cats—perhaps 50% more than respondents did) means. Rather than getting us any closer to the truth about cat predation, this study only obscured it further.

Worse, it’s been packaged and sold—and subsequently “bought”—as rigorous science, thereby giving it an undeserved legitimacy. Such efforts are impediments to knowledge and understanding—and therefore, to progress.

References
1. Lepczyk, C.A., et al., “What Conservation Biologists Can Do to Counter Trap-Neuter-Return: Response to Longcore et al.” Conservation Biology. 2010. 24(2): p. 627-629.

2. Lepczyk, C.A., Mertig, A.G., and Liu, J., “Landowners and cat predation across rural-to-urban landscapes.” Biological Conservation. 2003. 115(2): p. 191-201.

3. Barratt, D.G., “Predation by house cats, Felis catus (L.), in Canberra, Australia. II. Factors affecting the amount of prey caught and estimates of the impact on wildlife.” Wildlife Research. 1998. 25(5): p. 475–487.

4. Clancy, E.A., Moore, A.S., and Bertone, E.R., “Evaluation of cat and owner characteristics and their relationships to outdoor access of owned cats.” Journal of the American Veterinary Medical Association. 2003. 222(11): p. 1541-1545.

5. Coleman, J.S. and Temple, S.A., “Rural Residents’ Free-Ranging Domestic Cats: A Survey.” Wildlife Society Bulletin. 1993. 21(4): p. 381–390.

6. Barratt, D.G., “Predation by House Cats, Felis catus (L.), in Canberra, Australia. I. Prey Composition and Preference.” Wildlife Research. 1997. 24(3): p. 263–277.

7. Berkeley, E.P., TNR Past present and future: A history of the trap-neuter-return movement. 2004, Bethesda, MD: Alley Cat Allies.

8. Kuehn, B.M. and Kahler, S.C. The Cat Debate. JAVMA Online 2004 November 27, 2009 [accessed 2009 December 24]. http://www.avma.org/onlnews/javma/jan04/040115a.asp.

9. Longcore, T., Rich, C., and Sullivan, L.M., “Critical Assessment of Claims Regarding Management of Feral Cats by Trap–Neuter–Return.” Conservation Biology. 2009. 23(4): p. 887–894.

10. Dauphiné, N. and Cooper, R.J., Impacts of Free-ranging Domestic Cats (Felis catus) on birds in the United States: A review of recent research with conservation and management recommendations, in Fourth International Partners in Flight Conference: Tundra to Tropics. 2010. p. 205–219.

The Work Speaks—Part 5: Jumping to Conclusions

11 Jun 2010•Cats and Birds, Research Protocol, Threats to Wildlife

“…it may be that conservation biologists and wildlife ecologists believe the issue of feral cats has already been studied enough and that the work speaks for itself, suggesting that no further research is needed.”

In fact, “the work”—taken as a whole—is neither as rigorous nor as conclusive as Lepczyk et al. suggest. And far too much of it is plagued by exaggeration, misrepresentations, errors, and obvious bias. In Part 4 of this series, I discussed how feral cat/TNR researchers often misuse averages to characterize skewed distributions, and how that error overestimates the impact of free-roaming cats on wildlife.

For the next few posts, I’m going to critique three of the studies most often cited by these researchers, starting with Cole Hawkins’ 1998 PhD dissertation, Impact of a subsidized exotic predator on native biota: Effect of house cats (Felis catus) on California birds and rodents. I mentioned Hawkins’ dissertation previously, but only briefly. Here, I’ll take a closer look, paying particular attention to how he gets from his results to his rather dubious conclusions.

The Study
Hawkins’ two-year study was conducted in Alameda County, CA, spread across two adjacent parks. He started by designating a “cat area” (where, nearby, free-roaming cats were being fed) and a “no-cat area” (where no cats were being fed), and then designated “rodent grids” (nine locations used for trapping and counting rodents) and walking transects (from which bird surveys were conducted) in each area. Hawkins then compared the number of birds and rodents detected in the two areas.

Among Hawkins’ conclusions:

“The differences observed in this study were the results of the cat’s predatory behavior.” [2] (It should be noted that Hawkins tempered this assertion in his 1999 article summarizing the work: “The differences observed in this study may have been due to the cats’ predatory behavior.” [3] (italics mine))

And this:

“The presence of cats in this study area already has caused a shift in the composition of the rodent community; it is possible that a shift in the larger biotic community could follow.”

And, finally:

“It is not prudent to manage for wildlife and allow cat feeding in the same parks.”

Unfair Comparisons
But Hawkins’ findings are insufficient to supports such claims; indeed, his methodology doesn’t allow for them. Hawkins has no idea what the cat area was like prior to his arrival; he merely assumes the populations of birds and rodents would have been identical to those found at the no-cat area, and makes his comparisons accordingly. In fact, there are a number of factors that indicate that the two areas are not as comparable as Hawkins suggests:

The cat area was almost a peninsula, with a lake on one side and a residential area (within 0.5 km) on the other. The no-cat area, on the other hand, was located largely in the interior of the parks.
Hawkins notes that there were more people in the cat area (often twice as many as were observed at the no-cat area), but dismisses the possibility that their presence may have influenced the numbers of birds and rodents he observed there.
The habitat along the 2.2 km transects from which bird counts were conducted varied considerably between the two areas. Compared to the no-cat area, the cat area had 31% less chaparral, 183% more trees, 52% less grass, and 240% more “modified” habitat (it’s not clear what Hawkins means by “modified,” but I assume it refers to habitat that reflects significant human impact).
Finally, the presence of pesticides may have played a role. According to a 2002 report (the earliest I was able to find) from the East Bay Regional Park District, “The focus of Lake Chabot’s weed control efforts are vegetation reduction within the two-acre overflow parking lot, picnic sites and firebreaks around park buildings, corp. yard, service yard, and the Lake Chabot classroom.” [4] And it’s clear from Hawkins’ 1999 article that the cat area did include picnic sites: “…over half of the cat scat in this study was collected under and around picnic tables.” [3] Now, Hawkins’ fieldwork was done in 1995 and 1996, but if there was any pesticide use during the study period, it may have affected the results—especially if the pesticide was distributed differently across the two areas.

Cats and Birds
“Almost twice as many birds were seen on the no-cat transect as on the cat transect,” writes Hawkins. But it’s not quite as simple as that—the details reveal a rather complex, often uneven count over the course of the study. Nevertheless—and despite the differences between the two areas—Hawkins’ only explanation is the cats. This is especially true for ground-feeders:

The preference of ground feeding birds for the no-cat treatment was striking; for example, California quail were seen almost daily in the no-cat area, whereas they were never seen in the cat area.

What’s more striking to me is the fact that five of the nine ground-feeding species included in the study showed no preference for either area. But Hawkins scarcely acknowledges the point, and doesn’t even hint at an explanation. “Birds that were known to nest on or near the ground or in shrubs and vines ≤ 1.5 m in height” also showed no preference between the two areas (though no nest counts were conducted).

The picture painted by Hawkins is that bird species absent from the cat area represent species killed off by the cats. But it’s generally accepted that cats are opportunistic hunters, catching whatever prey is readily available and easily caught. [5–8] Fitzgerald and Turner, for example, argue that “domestic cats (both house and feral ones) are best described as generalist resident predators, exploiting a wide range of prey, and able to switch readily from one prey to another.” [9] So, how is it that some species were present at the cat site while others were not? Again, Hawkins offers no explanation.

In fact, it’s clear from Hawkins’ study that the cats aren’t much of threat at all to the birds—even vulnerable ground-feeding and ground-nesting species—in the cat area. Of the 120 scat samples found by searching the cat area, “65% were found to contain rodent hair and 4% feathers.” [2] This finding comes toward the end of the study, when the cat population was at its greatest—and still, only 4% contained feathers. And this could easily represent one cat and one bird.

One final point about the birds: Hawkins suggests (without explanation) that the olive-sided flycatcher, American robin, and Stellar’s jay—all of which showed no preference for either the no-cat area or the cat area—may have been responding to a “specialized habitat.” Could it be that the birds not seen in the cat area were also responding to a specialized habitat—by “migrating” to a place with less human activity (e.g., the no-cat area), for example? Once again, Hawkins has no comment.

Cats and Rodents
The fact that scats indicated rodents were predated to a greater extent than birds is hardly surprising [5, 6, 9, 10], but it should be noted the 65% figure represents the frequency of occurrence, and not a predation rate (a topic I address in greater detail here).

Hawkins’ analysis didn’t reveal whether the rodent hair was that of deer mice, harvest mice (both of which were found less often in the cat area than in the no-cat area), house mice (found more often in the cat area), or California voles (which showed no preference for either area). In any case, it’s not clear that the cats were responsible for the presence or absence of any of these rodent species. Again, the selective dietary habits suggested by Hawkins simply don’t fit with the domestic cat’s profile as a “generalist resident predator.”

Two additional points that might explain the differences Hawkins observed concern the habitat of the cat area. First, there’s the nearby lake and residences—potential sources of pollution that could affect nearby plant and animal life. Secondly, there’s the issue of possible pesticide use mentioned previously. As I say, it’s largely conjecture on my part; at the same time, though, it’s easy to imagine its potential impact on small mammals (and ground-feeding birds, for that matter).

Finally, Hawkins suggests that certain bird species were responding to specialized habitat—perhaps the rodents were simply doing the same.

Cats
Hawkins used track plates (baited devices that detect the presence of mammals by way of preserved “footprints”) for “estimating a relative cat presence index,” but found only one cat track in 200 track plate nights. And, “in 560 days of exposure, no scat was found in any of the sand boxes.” [2] Now, the cats were seen at feeding stations and on the rodent grids of the cat area—as many as 26 during a one-week period toward the end of the study. But clearly, they were not where Hawkins was expecting them to be. If, after two years at the study site, Hawkins was unable to get a better handle on the presence of the cats, how can he be so sure of their behavior when it comes to predation?

If, as Hawkins argues, the differences observed between the two areas are a result of the cats’ predatory behavior, then one would expect the number of birds and rodents to decrease as the number of cats increases. Yet, Hawkins’ findings don’t bear this out.

And then there are the unanswered questions about the cats—for example:

Where did these cats come from—were they illegally dumped, the result of nearby residents’ unsterilized cats breeding? Did they belong to the residents?
Were the cats sterilized? (Their increasing numbers would suggest that they weren’t.)
Were these cats part of a managed TNR colony? (Local newspaper reports indicate a long-standing battle between TNR advocates and opponents. [11–13])

Considering the central role these cats played in Hawkins’ two-year study, he knew surprisingly little about their behavior—including various factors that surely had an impact on his findings.

* * *

In their recent comment, Lepczyk et al. suggest that conservation biologists and wildlife ecologists “look to the evolutionary biology community” [1] for an example of how to influence policy. For feral cat/TNR opponents interested in shaping policy, it seems Hawkins’ study has become quite popular. [14–17] Actually, Nico Dauphiné and Robert J. Cooper take its already-tenuous claims one step further, citing Hawkins’ work (actually a 2004 conference paper that summarizes his dissertation [18]) as evidence that “the continuous predation pressure exerted by exotic predators in exponentially high densities can and has resulted in numerous local extinctions of continental land birds.” [8]

But is Hawkins’ methodology one that evolutionary biologists would advocate—or even recognize? Not likely.

Hawkins draws conclusions—infers important causal relationships—without any evidence of what “pre-treatment” conditions were like. And ignores entirely his own findings when they contradict his conclusions. Rather than beginning his inquiry with questions to answer, it seems Hawkins had his answer from the outset. At best, his work is an interesting pilot study—generating research questions for a more rigorous, less biased investigation.

References
1. Lepczyk, C.A., et al., “What Conservation Biologists Can Do to Counter Trap-Neuter-Return: Response to Longcore et al.” Conservation Biology. 2010. 24(2): p. 627-629.

2. Hawkins, C.C., Impact of a subsidized exotic predator on native biota: Effect of house cats (Felis catus) on California birds and rodents. 1998, Texas A&M University.

3. Hawkins, C.C., Grant, W.E., and Longnecker, M.T., “Effects of Subsidized House Cats on California Birds and Rodents.” Transactions of the Western Section of the Wildlife Society. 1999. 35: p. 29–33.

4. Brownfield, N.T., 2002 Annual Analysis of Pesticide Use East Bay Regional Park District. 2003, East Bay Regional Park District. www.ebparks.org/files/stew_pest_report_02.pdf

5. Barratt, D.G., “Predation by house cats, Felis catus (L.), in Canberra, Australia. II. Factors affecting the amount of prey caught and estimates of the impact on wildlife.” Wildlife Research. 1998. 25(5): p. 475–487.

6. Fitzgerald, B.M., Diet of domestic cats and their impact on prey populations, in The Domestic cat: The biology of its behaviour, D.C. Turner and P.P.G. Bateson, Editors. 1988, Cambridge University Press: Cambridge; New York. p. 123–147.

7. Lepczyk, C.A., Mertig, A.G., and Liu, J., “Landowners and cat predation across rural-to-urban landscapes.” Biological Conservation. 2003. 115(2): p. 191-201.

8. Dauphiné, N. and Cooper, R.J., Impacts of Free-ranging Domestic Cats (Felis catus) on birds in the United States: A review of recent research with conservation and management recommendations, in Fourth International Partners in Flight Conference: Tundra to Tropics. 2010. p. 205–219.

9. Fitzgerald, B.M. and Turner, D.C., Hunting Behaviour of domestic cats and their impact on prey populations, in The Domestic Cat: The biology of its behaviour, D.C. Turner and P.P.G. Bateson, Editors. 2000, Cambridge University Press: Cambridge, U.K.; New York. p. 151–175.

10. Woods, M., McDonald, R.A., and Harris, S., “Predation of wildlife by domestic cats Felis catus in Great Britain.” Mammal Review. 2003. 33(2): p. 174-188.

11. Chui, G., Stray Cats Live Harsh Lives in Area Parks, in San Jose Mercury News. 1985. p. 1

12. Bogue, G., Those Poor Cats Need a Human Assist, in Contra Costa Times. 1997: Walnut Creek, CA. p. A02

13. n.a., Spring controversy: What to do with feral cats?, in San Mateo Daily Journal, The (CA). 2001.

14. Longcore, T., Rich, C., and Sullivan, L.M., “Critical Assessment of Claims Regarding Management of Feral Cats by Trap–Neuter–Return.” Conservation Biology. 2009. 23(4): p. 887–894.

15. ABC, Domestic Cat Predation on Birds and Other Wildlife. n.d., American Bird Conservancy: The Plains, VA. www.abcbirds.org/abcprograms/policy/cats/materials/predation.pdf

16. Winter, L. and Wallace, G.E., Impacts of Feral and Free-Ranging Cats on Bird Species of Conservation Concern, G.E. Wallace, Editor. 2006, American Bird Conservancy. www.abcbirds.org/newsandreports/NFWF.pdf

17. Ash, S.J. and Adams, C.E., “Public Preferences for Free-Ranging Domestic Cat (Felis catus) Management Options.” Wildlife Society Bulletin. 2003. 31(2): p. 334–339.

18. Hawkins, C.C., Grant, W.E., and Longnecker, M.T. Effect of house cats, being fed in parks, on California birds and rodents. in Proceedings Of The 4th International Symposium On Urban Wildlife Conservation. 2004. Tucson, AZ: University of Arizona. http://cals.arizona.edu/pubs/adjunct/snr0704/snr07042l.pdf

The Work Speaks—Part 4: Mean Spirited

4 Jun 2010•Population Estimates, Research Protocol, Threats to Wildlife

“…it may be that conservation biologists and wildlife ecologists believe the issue of feral cats has already been studied enough and that the work speaks for itself, suggesting that no further research is needed.”

In fact, “the work”—taken as a whole—is neither as rigorous nor as conclusive as Lepczyk et al. suggest. And far too much of it is plagued by exaggeration, misrepresentations, errors, and obvious bias. In Part 3 of this series, I discussed the distinction between compensatory and additive predation. Here, I’ll focus on how feral cat/TNR researchers often misuse averages to characterize skewed distributions, and how that error overestimates the impact of free-roaming cats on wildlife.

Something’s Askew
When a data set is skewed, it is inappropriate to use the mean, or average, as a measure of central tendency. The mean should be used only when the data set can be considered normal—the familiar bell curve. As Woods et al put it:

“the simple average number of animals brought home is not a useful measure of central tendency because of the skewed frequency distribution of the numbers of prey items brought home…” [2]

Studies of cat predation routinely reveal a positively skewed distribution; a few cats are responsible for many kills, while many of the cats kill few, if any, prey. So when researchers use the mean to calculate the total number of prey killed by cats in a particular area, they overestimate the cats’ impact.

How common is this? Very [see, for example, 3-9]. Of the many cat predation studies I’ve read, only a few [2, 10, 11] properly account for the skewed nature of this distribution. And others [12-17] often take these inflated figures at face value—as evidence of the impact cats have on wildlife. Published repeatedly, the erroneous estimates take on an undeserved legitimacy.

The proper method for handling skewed distributions involves data transformations, the details of which I won’t go into here. The important point is this: in the case of a positively skewed distribution, the back-transformed mean will always be less than the simple mean of the same data set.

Big Deal
Depending on the particular distribution, the difference between the simple mean and the back-transformed mean can be considerable. Let’s use the 2003 study by Woods et al. [2] to illustrate. In the case of mammals killed and returned home by pet cats, the back-transformed mean was 28.3% less than the simple mean. Or, put another way, the simple mean would have overestimated the number of mammals killed by 39.5%. Similarly, when all prey items were totaled (as depicted in the illustration above), the simple mean would have overestimated the total number off all prey (mammals, birds, herpetofauna, and “others”) by 46.9%.

On the other hand, the figures for birds appear to break the rule mentioned above. In this case, the back-transformed mean (4.1) is actually a bit higher than the simple mean (4.0). How can this be? In order to log-transform the data set, Woods et al. had to first eliminate all the instances where cats returned home no prey—you can’t take the logarithm of 0. So, they were actually working with two data sets. Now, the second data set—which includes only those cats that returned at least one prey item—is also highly positively skewed. As a point of reference, its simple mean was approximately 5.6 birds/cat, which, compared to the back-transformed mean, is an overestimation of 37.5%.

By now, it should be apparent that log-transformed means have another important advantage over simple means: because you have to eliminate those zeros from the data set, you are forced to focus only on the cats that returned prey home—which, of course, is the whole point of such studies! And in the case of this study, Woods et al. found that 20–30% of cats brought home either no birds or no mammals. And 8.6% of the cats brought home no prey at all over the course of the study.

Transforming a data set (and then back-transforming its mean) is simpler than it sounds, but Barratt offers a useful alternative, rule-of-thumb method (one echoed by Fitzgerald and Turner [18]):

“…median numbers of prey estimated or observed to be caught per year are approximately half the mean values, and are a better representation of the average predation by house cats based on these data.” [10]

So, whereas Dauphiné and Cooper (and others) suggest increasing such estimates by factors of two and three (“predation rates measured through prey returns may represent one half to less than one third of what pet cats actually kill…” [14]), they should, in fact, be reducing them by half.

Cat Ownership
There are other instances in which simple averages are used to describe similarly skewed distributions—with similar results. That is, they overestimate a particular characteristic—and not in the cats’ favor.

Cat ownership, for example, is not a normal distribution. Many people own one or two cats; a few people own many cats. This is precisely what Lepczyk et al. found in their 2003 study:

“The total number of free-ranging cats across all landscapes was 656, ranging from 1 to 30 per landowner…” [6]

In fact, about 113 (I’m estimating from the histogram printed in the report) of those landowners owned just one cat apiece. About 70 of them owned two cats. Only one—maybe two—owned 30 cats. And yet, Lepczyk et al. calculate an average of 2.59 cats/landowner (i.e., 656 cats/253 landowners who allow their cats outdoors), thereby substantially overestimating cat ownership—and, in turn, predation rates (which calculations are based upon the average number of cats/landowner).

Lepczyk et al. are not the only ones to make this mistake; several other researchers have done the same. [4, 5, 7-9]

Outdoor Access
The amount of time cats spend outdoors is also highly positively skewed, as is apparent from the 2003 survey conducted by Clancy, Moore, and Bertone. [19] Their work showed that nearly half of the cats with outdoor access were outside for two or fewer hours a day. And 29% were outdoors for less than an hour each day.

Among those researchers to overlook the skewed nature of this distribution are Kays and DeWan, who calculate an average of 8.35 hours/day. This greatly overestimates potential predation, and leads them to conclude—erroneously—that the actual number of prey killed by cats was “3.3 times greater than the rate estimated from prey brought home,” [9] as was discussed previously.

Compound Errors
Clearly, these errors are substantial—in some cases, doubling the apparent impact of cats on wildlife. Of course the errors are even more significant when one inflated figure is multiplied by another—as when Lepczyk et al. [6] multiply the average number of prey items returned by the average number of outdoor cats per owner. The resulting predation figures may well be four times greater than they should be! (Actually, there are additional problems with the authors’ predation estimates, which I’ll address in a future post).

* * *

The fact that such a fundamental mistake—one a student couldn’t get away with in a basic statistics course—is made so often is shocking. The fact that such errors slip past journal reviewers is inexcusable.

References
1. Lepczyk, C.A., et al., “What Conservation Biologists Can Do to Counter Trap-Neuter-Return: Response to Longcore et al.” Conservation Biology. 2010. 24(2): p. 627-629.

2. Woods, M., McDonald, R.A., and Harris, S., “Predation of wildlife by domestic cats Felis catus in Great Britain.” Mammal Review. 2003. 33(2): p. 174-188.

3. Coleman, J.S. and Temple, S.A., On the Prowl, in Wisconsin Natural Resources. 1996, Wisconsin Department of Natural Resources: Madison, WI. p. 4–8. http://dnr.wi.gov/wnrmag/html/stories/1996/dec96/cats.htm

4. Baker, P.J., et al., “Impact of predation by domestic cats Felis catus in an urban area.” Mammal Review. 2005. 35(3/4): p. 302-312.

5. Baker, P.J., et al., “Cats about town: is predation by free-ranging pet cats Felis catus likely to affect urban bird populations?“ Ibis. 2008. 150: p. 86-99.

6. Lepczyk, C.A., Mertig, A.G., and Liu, J., “Landowners and cat predation across rural-to-urban landscapes.” Biological Conservation. 2003. 115(2): p. 191-201.

7. Crooks, K.R., et al., “Exploratory Use of Track and Camera Surveys of Mammalian Carnivores in the Peloncillo and Chiricahua Mountains of Southeastern Arizona.” The Southwestern Naturalist. 2009. 53(4): p. 510-517.

8. van Heezik, Y., et al., “Do domestic cats impose an unsustainable harvest on urban bird populations?“ Biological Conservation. 143(1): p. 121-130.

9. Kays, R.W. and DeWan, A.A., “Ecological impact of inside/outside house cats around a suburban nature preserve.” Animal Conservation. 2004. 7(3): p. 273-283.

10. Barratt, D.G., “Predation by house cats, Felis catus (L.), in Canberra, Australia. II. Factors affecting the amount of prey caught and estimates of the impact on wildlife.” Wildlife Research. 1998. 25(5): p. 475–487.

11. Barratt, D.G., “Predation by House Cats, Felis catus (L.), in Canberra, Australia. I. Prey Composition and Preference.” Wildlife Research. 1997. 24(3): p. 263–277.

12. May, R.M., “Control of feline delinquency.” Nature. 1988. 332(March): p. 392-393.

13. Jessup, D.A., “The welfare of feral cats and wildlife.” Journal of the American Veterinary Medical Association. 2004. 225(9): p. 1377-1383.

14. Dauphiné, N. and Cooper, R.J., Impacts of Free-ranging Domestic Cats (Felis catus) on birds in the United States: A review of recent research with conservation and management recommendations, in Fourth International Partners in Flight Conference: Tundra to Tropics. 2010. p. 205–219

15. Longcore, T., Rich, C., and Sullivan, L.M., “Critical Assessment of Claims Regarding Management of Feral Cats by Trap–Neuter–Return.” Conservation Biology. 2009. 23(4): p. 887–894.

16. Winter, L., “Trap-neuter-release programs: the reality and the impacts.” Journal of the American Veterinary Medical Association. 2004. 225(9): p. 1369-1376.

17. Clarke, A.L. and Pacin, T., “Domestic cat “colonies” in natural areas: a growing species threat.” Natural Areas Journal. 2002. 22: p. 154–159.

18. Fitzgerald, B.M. and Turner, D.C., Hunting Behaviour of domestic cats and their impact on prey populations, in The Domestic Cat: The biology of its behaviour, D.C. Turner and P.P.G. Bateson, Editors. 2000, Cambridge University Press: Cambridge, U.K.; New York. p. 151–175.

19. Clancy, E.A., Moore, A.S., and Bertone, E.R., “Evaluation of cat and owner characteristics and their relationships to outdoor access of owned cats.” Journal of the American Veterinary Medical Association. 2003. 222(11): p. 1541-1545.

The Work Speaks—Part 3: Predatory Blending?

31 May 2010•Population Estimates, Threats to Wildlife

“…it may be that conservation biologists and wildlife ecologists believe the issue of feral cats has already been studied enough and that the work speaks for itself, suggesting that no further research is needed.”

In fact, “the work”—taken as a whole—is neither as rigorous nor as conclusive as Lepczyk et al. suggest. And far too much of it is plagued by exaggeration, misrepresentations, errors, and obvious bias. In a previous post, I presented examples of researchers drawing big conclusions from small sample sizes. Here, I’ll discuss the important distinction between compensatory and additive predation—a point too often left out of the feral cat/TNR discussion.

Sins of Omission
Focusing on the number of prey injured or killed by cats, without also recognizing that there are different types of predation, implies that each and every bird, mammal, reptile, etc. is destined to be part of its species’ breeding population. Of course, that’s not at all how things work out in the natural world—with or without predation by cats.

And yet, numerous studies [2-10], reviews [11], and other published papers [12-14] fail to acknowledge the critical difference between compensatory predation (in which prey would have died even in the absence of a particular predator, due to illness, starvation, other predators, etc.) and additive predation (in which healthy prey are killed). It’s the difference between, as Beckerman et al. put it, the “doomed surplus hypothesis” and the “hapless survivor hypothesis.” [15]

This is a critical point when it comes to connecting predation rates (from cats or any other predator) to population impacts. The more additive the predation, the greater the potential impact on population numbers. Purely compensatory predation, on the other hand, is less likely to affect overall populations. Of course, the connection is seldom so simple and direct, and a number of factors (e.g., habitat area and type, base population numbers, etc.) influence the ultimate outcome—making it quite difficult to tease out specific causal relationships. Nevertheless, if we want to better understand the impact of free-roaming cats on wildlife, we cannot ignore the distinction between—and inherent implications of—these two types of predation.

Honorable Mentions
Although Churcher and Lawton failed to mention the distinction between compensatory and additive predation in their now-classic “English village” study [4], Churcher later suggested that their findings were largely in the compensatory category: “If the cats weren’t there, something else would be killing the sparrows or otherwise preventing them from breeding.” [16]

Woods et al. don’t address the topic directly, but warn against drawing direct connections between predation numbers and potential effects on population dynamics:

“Our estimates of the total numbers of animals brought home by cats throughout Britain should be treated with requisite caution and these figures do not equate to an assessment of the impact of cats on wildlife populations.” [3]

Unfortunately, other researchers have used this study to make exactly that connection. In “Critical Assessment,” for example, Longcore et al. cite Woods et al. (along with Lepczyk et al. 2003, the subject of a future post) when they write, “evidence indicates that cats can play an important role in fluctuations of bird populations.” [11]

Under-Compensating?
In their 2008 study, Baker et al. found that “birds killed by cats in this study had significantly lower fat and pectoral muscle mass scores than those killed by collisions,” [17] suggesting that they may have been among the “doomed surplus” portion of the population. Similar results were reported eight years earlier by Møller and Erritzøe, who found that “small passerine birds falling prey to cats had spleens that were significantly smaller than those of conspecifics that died for other reasons,” concluding ultimately that the birds killed by cats “often have a poor health status.” [18]

But Baker et al. express caution about their findings:

“…the distinction between compensatory and additive mortality does… become increasingly redundant as the number of birds killed in a given area increases: where large numbers of prey are killed, predators would probably be killing a combination of individuals with poor and good long-term survival chances.”

Whatever their concerns, it must be noted that Baker et al. inflated their predation numbers by a factor of 3.3 on the basis of Kays and DeWan’s dubious conclusions [9] (which I discussed in some detail previously). Doing so raises considerable doubts about any level of “redundancy,” as well the authors’ suggestion that cat predation in the area might be “creating a dispersal sink for more productive neighboring areas.” [19] (Such “sinks” can occur when predation outstrips local prey populations, requiring that prey be “recruited” from surrounding areas.)

Implications
Given all the work that’s been done on cat predation, one might expect the subject of compensatory predation to be addressed more fully and more often. By omitting this important issue from the feral cat/TNR discussion, researchers portray a situation both simpler and harsher (in terms of what it implies about the impact of free-roaming cats) than reality suggests. Whether or not such omissions are intentional, I cannot say. I do, however, find it curious—what’s included compared to what’s left out, and by whom.

References
1. Lepczyk, C.A., et al., “What Conservation Biologists Can Do to Counter Trap-Neuter-Return: Response to Longcore et al.” Conservation Biology. 2010. 24(2): p. 627-629.

2. Coleman, J.S. and Temple, S.A., On the Prowl, in Wisconsin Natural Resources. 1996, Wisconsin Department of Natural Resources: Madison, WI. p. 4–8. http://dnr.wi.gov/wnrmag/html/stories/1996/dec96/cats.htm

3. Woods, M., McDonald, R.A., and Harris, S., “Predation of wildlife by domestic cats Felis catus in Great Britain.” Mammal Review. 2003. 33(2): p. 174-188.

4. Churcher, P.B. and Lawton, J.H., “Predation by domestic cats in an English village.” Journal of Zoology. 1987. 212(3): p. 439-455.

5. Coleman, J.S. and Temple, S.A., “Rural Residents’ Free-Ranging Domestic Cats: A Survey.” Wildlife Society Bulletin. 1993. 21(4): p. 381–390.

6. Coleman, J.S. and Temple, S.A., Effects of Free-Ranging Cats on Wildlife: A Progress Report, in Fourth Eastern Wildlife Damaage Control Conference. 1989: University of Nebraska—Lincoln. p. 8–12. http://digitalcommons.unl.edu/ewdcc4/7

7. Hawkins, C.C., Impact of a subsidized exotic predator on native biota: Effect of house cats (Felis catus) on California birds and rodents. 1998. PhD Dissertation, Texas A&M University.

8. Hawkins, C.C., Grant, W.E., and Longnecker, M.T., “Effects of Subsidized House Cats on California Birds and Rodents.” Transactions of the Western Section of the Wildlife Society. 1999. 35: p. 29–33.

9. Kays, R.W. and DeWan, A.A., “Ecological impact of inside/outside house cats around a suburban nature preserve.” Animal Conservation. 2004. 7(3): p. 273-283.

10. Lepczyk, C.A., Mertig, A.G., and Liu, J., “Landowners and cat predation across rural-to-urban landscapes.” Biological Conservation. 2003. 115(2): p. 191-201.

11. Longcore, T., Rich, C., and Sullivan, L.M., “Critical Assessment of Claims Regarding Management of Feral Cats by Trap–Neuter–Return.” Conservation Biology. 2009. 23(4): p. 887–894.

12. Dauphiné, N. and Cooper, R.J., Impacts of Free-ranging Domestic Cats (Felis catus) on birds in the United States: A review of recent research with conservation and management recommendations, in Fourth International Partners in Flight Conference: Tundra to Tropics. 2010. p. 205–219

13. Coleman, J.S., Temple, S.A., and Craven, S.R., Cats and Wildlife: A Conservation Dilemma. 1997, University of Wisconsin, Wildlife Extension. http://forestandwildlifeecology.wisc.edu/wl_extension/catfly3.htm

14. Andersen, M.C., Martin, B.J., and Roemer, G.W., “Use of matrix population models to estimate the efficacy of euthanasia versus trap-neuter-return for management of free-roaming cats.” Journal of the American Veterinary Medical Association. 2004. 225(12): p. 1871-1876.

15. Beckerman, A.P., Boots, M., and Gaston, K.J., “Urban bird declines and the fear of cats.” Animal Conservation. 2007. 10(3): p. 320-325.

16. n.a., What the Cat Dragged In, in Catnip. 1995, Tufts University School of Veterinary Medicine: Boston, MA. p. 4–6

17. Baker, P.J., et al., “Cats about town: is predation by free-ranging pet cats Felis catus likely to affect urban bird populations?“ Ibis. 2008. 150: p. 86-99.

18. Møller, A.P. and Erritzøe, J., “Predation against birds with low immunocompetence.” Oecologia. 2000. 122(4): p. 500-504.

The Work Speaks—Part 2: Sample-Minded Research

27 May 2010•Population Estimates, Research Protocol, The Cat Debate, Threats to Wildlife

“…it may be that conservation biologists and wildlife ecologists believe the issue of feral cats has already been studied enough and that the work speaks for itself, suggesting that no further research is needed.”

In fact, “the work”—taken as a whole—is neither as rigorous nor as conclusive as Lepczyk et al. suggest. And far too much of it is plagued by exaggeration, misrepresentations, errors, and obvious bias. In my previous post, I presented examples of researchers “reinterpreting” the work of others to better fit their own arguments. For the next few posts, I’ll focus on some of the major flaws in the feral cat/TNR research itself—beginning with the reliance, by some, on small sample sizes.

Size Does Matter
There are all kinds of reasons for small sample sizes, perhaps the most common being limited resources (e.g., time, funding, etc.). And they are often a fact of life in real-world research, where investigators have less control over conditions than they might in a laboratory environment. Studies employing small sample sizes are not without value; indeed, they often serve as useful pilot studies for future, more comprehensive, work. They do become problematic, though, when broad conclusions are drawn from their results. Below are three (among many!) examples of such studies.

Impressive Estimates
In “Free-Ranging Domestic Cat Predation on Native Vertebrates in Rural and Urban Virginia,” [2] published in 1992, the authors estimated that the state’s 1,048,704 cats were killing between 3,146,112 and 26,217,600 songbirds each year. “This number,” they note, “is certainly inaccurate to some degree, although the estimates are impressive.” [2] Impressive? I suppose. Maybe incredible is more fitting—since the study from which they were derived included exactly five cats, four “urban” and one “rural.”

Mitchell and Beck acknowledged “the limitations of extrapolation to large areas from relatively small data sets such as ours,” suggesting that their work was intended to provoke future “careful and detailed studies that can reveal truer estimates of the impact of this introduced species.” Hawkins [3] and Dauphiné and Cooper [4], however, seem to take them at their word, regardless of any disclaimers.

Many Cats, Multiple Seasons
In a recent study on Catalina Island, the researchers “examined the home-range behavior and movements of sterilized and intact radiocollared feral cats living in the interior” [5] of the island. Although Guttilla and Stapp concede that “sample sizes, especially for males, were relatively low” despite having “tracked many cats across multiple seasons,” they nevertheless come to some rather dramatic conclusions. Among them: “sterilization likely would not reduce the impact of feral cats on native prey.” [5]

So what do the authors mean by many and multiple? Actually, there were just 27 cats in the study (of an estimated 614–732 on the island). “Four cats were tracked during all four seasons, 9 cats were tracked for three consecutive seasons, 4 cats were tracked for 2 consecutive seasons, and the remaining cats were tracked for 1 season.” [5] And these numbers were effectively cut in half, because the researchers were comparing sterilized and non-sterilized cats. At best, this is a pilot study—though it’s already morphed into something more substantial in the mainstream media.

Myth vs. Math
In their 2004 study, “Ecological Impact of Inside/Outside House Cats Around a Suburban Nature Preserve,” Kays and DeWan observed hunting cats, concluding that their kill rate (13%) is “3.3 times greater than the rate estimated from prey brought home.” [6] Not surprisingly, this figure has been used as an instant multiplier (much in the same way William George’s work has been misused) for researchers interested in “correcting” (inflating?) prey numbers. [4, 7-11]

But this ratio, 3.3, hinges on the hunting behaviors of just 24 cats—12 that returned prey home, and another 12 (11 pets and 1 feral) that were observed hunting for a total of 181 hours (anywhere from 4.8–46.5 hours per cat). It’s interesting to note that the cat observed the most (46.5 hours) was only a year old—the youngest of the 12 observed, and likely the most active hunter. This factor alone could have had a significant influence on the outcome of the study.

Also, as several studies have shown [7,8,12,13], the distribution of prey catches tends to be highly skewed (many cats catch few/no prey, while a few catch a lot). In other words, the distribution is not the familiar bell curve at all—making it inappropriate to use a simple average for calculating estimations (a topic I’ll address in detail later). What’s more, with only 12 cats being monitored, how can we be sure their behaviors accurately represent any real distribution at all?

But the key to their calculation is the average time spent outdoors. This, too, tends to be a highly skewed distribution [14, 15], although—curiously—Kays and DeWan’s data suggest otherwise. By way of example, a 2003 survey conducted by Clancy, Moore, and Bertone [15] revealed that nearly half of the cats with outdoor access were outside for two or fewer hours a day. And 29% were outdoors for less than an hour each day. A survey conducted by the American Bird Conservancy revealed similar behavior, reporting that “35% keep their cats indoors all of the time” and “31% keep them indoors mostly with some outside access.” [14]

Kays and DeWan’s average of 8.35 hours/day, then, seems rather out of line with other studies. This, in addition to a number of unknowns (e.g., influence of time of day/night on hunting success, actual time spent hunting by each cat, etc.) raises serious questions about their conclusions.

By way of comparison, using an average of 2.5 hours/day (which is not out of line with the surveys described above) would yield a ratio of 1:1. In other words, no difference between predation rates predicted by actual hunting observation and those predicted by way of prey returned home. Which is not to say that I agree with Kays and DeWan’s underlying methods—we don’t know the possible effects of seasonal variation, for example, or differences in habitat. I’m only pointing out how sensitive this one factor—with its enormous consequences—is to the amount of time cats actually spend outdoors (and, just to introduce one more complication: I’d be very surprised if the amount of outdoor time cats spend hunting is normally distributed; it, too, is probably skewed).

Ironically, while the authors express disappointment that “biologists have rarely sampled both cat and prey populations in such a way that direct effects on prey populations can be shown,” [6] they seem to have had no misgivings about how their work—suffering from its own sampling issues—might be used to misrepresent those same effects.

* * *

Next, I’ll discuss the difference between compensatory and additive predation, and how that affects predictions of feral cat impacts on wildlife.

References
1. Lepczyk, C.A., et al., “What Conservation Biologists Can Do to Counter Trap-Neuter-Return: Response to Longcore et al.” Conservation Biology. 2010. 24(2): p. 627-629.

2. Mitchell, J.C. and Beck, R.A., “Free-Ranging Domestic Cat Predation on Native Vertebrates in Rural and Urban Virginia.” Virginia Journal of Science. 1992. 43(1B): p. 197–207.

3. Hawkins, C.C., Impact of a subsidized exotic predator on native biota: Effect of house cats (Felis catus) on California birds and rodents. 1998. PhD Dissertation, Texas A&M University.

4. Dauphiné, N. and Cooper, R.J., Impacts of Free-ranging Domestic Cats (Felis catus) on birds in the United States: A review of recent research with conservation and management recommendations, in Fourth International Partners in Flight Conference: Tundra to Tropics. 2010. p. 205–219

5. Guttilla, D.A. and Stapp, P., “Effects of sterilization on movements of feral cats at a wildland-urban interface.” Journal of Mammalogy. 2010. 91(2): p. 482-489.

6. Kays, R.W. and DeWan, A.A., “Ecological impact of inside/outside house cats around a suburban nature preserve.” Animal Conservation. 2004. 7(3): p. 273-283.

7. Baker, P.J., et al., “Impact of predation by domestic cats Felis catus in an urban area.” Mammal Review. 2005. 35(3/4): p. 302-312.

8. Baker, P.J., et al., “Cats about town: is predation by free-ranging pet cats Felis catus likely to affect urban bird populations?“ Ibis. 2008. 150: p. 86-99.

9. van Heezik, Y., et al., “Do domestic cats impose an unsustainable harvest on urban bird populations?“ Biological Conservation. 143(1): p. 121-130.

10. Nelson, S.H., Evans, A.D., and Bradbury, R.B., “The efficacy of collar-mounted devices in reducing the rate of predation of wildlife by domestic cats.” Applied Animal Behaviour Science. 2005. 94(3-4): p. 273-285.

11. MacLean, M.M., et al., “The usefulness of sensitivity analysis for predicting the effects of cat predation on the population dynamics of their avian prey.” Ibis. 2008. 150(Suppl. 1): p. 100-113.

12. Churcher, P.B. and Lawton, J.H., “Predation by domestic cats in an English village.” Journal of Zoology. 1987. 212(3): p. 439-455.

13. Woods, M., McDonald, R.A., and Harris, S., “Predation of wildlife by domestic cats Felis catus in Great Britain.” Mammal Review. 2003. 33(2): p. 174-188.

14. ABC, Human Attitudes and Behavior Regarding Cats. 1997, American Bird Conservancy: Washington, DC. http://www.abcbirds.org/abcprograms/policy/cats/materials/attitude.pdf

15. Clancy, E.A., Moore, A.S., and Bertone, E.R., “Evaluation of cat and owner characteristics and their relationships to outdoor access of owned cats.” Journal of the American Veterinary Medical Association. 2003. 222(11): p. 1541-1545.

The Work Speaks—Part 1: Lost in Translation

24 May 2010•Cats and Birds, Research Protocol, The Cat Debate, Threats to Wildlife

“…it may be that conservation biologists and wildlife ecologists believe the issue of feral cats has already been studied enough and that the work speaks for itself, suggesting that no further research is needed.”

In fact, “the work”—taken as a whole—is neither as rigorous nor as conclusive as Lepczyk et al. suggest. And far too much of it is plagued by exaggerations, misrepresentations, errors, and obvious bias. For the next few posts, I’m going to present a sampling of its more serious flaws, beginning with how some researchers “reinterpret” work of others to suit their own purposes.

Tell It Like It Is
Studies of cat predation frequently cite the work of William G. George, who, in 1974, published a paper documenting his meticulous observations of the hunting behavior of three cats on his southern Illinois farm. “The results,” wrote George, “established a basis for examining the possibility that cat predation may result in depleted winter populations of microtine rodents and other prey of Red-tailed Hawks, Marsh Hawks, and American Kestrels.” [2]

Thirty years later, David A. Jessup interpreted things rather differently, giving George’s work an additional—and unwarranted—degree of certainty. Gone are the doubts that George expressed—first, regarding the impact of cat predation on rodent and other prey populations; second, regarding the relationship between these populations and the raptors that feed on them. For Jessup—who offers no additional evidence—it’s all very straightforward: “Feral cats also indirectly kill native predators by removing their food base.” [3]

More recently, Guttilla and Stapp seem to prefer Jessup’s take: “Human-subsidized cats… can spill over into less densely populated wildland areas where they reduce prey for native predators (George 1974).” [4]

If any additional work has been done on the subject (surely there are more cats in the area these days; how are the voles and raptors faring?), it seems to have gone unnoticed. Instead, Jessup, Guttilla, and Stapp (and others, too, no doubt) have simply rewritten George’s conclusion to suit their own purposes. Perhaps their version makes for a better story, but it’s rather poor science.

Credit Where Little/None Is Due
When the Lancet recently retracted a 1998 paper linking vaccinations to autism in children—“research” that sparked the ongoing backlash against vaccinations—it was headline news. The move prompted this criticism from one member of the British Parliament: “The Lancet article should never have been published, and its peer review system failed. The article should now be expunged from the academic record…”

At the risk of drawing too many parallels between the two papers, I think the same can be said for Coleman and Temple’s infamous “Wisconsin Study.” (On the other hand, it does serve a useful purpose as a red flag.) Actually, as Goldstein et al. point out, Coleman and Temple’s paper was never peer-reviewed (not necessarily a deal-breaker in my book, but such publications do warrant additional scrutiny), but achieved its mythical status by being cited ad nauseam in peer-reviewed journals, as well as the mainstream media.

Does anybody actually believe the numbers suggested by Coleman and Temple? Stanley Temple (one of the co-authors of the recent anti-feral cat/TNR comment in Conservation Biology) himself admitted their published figures “aren’t actual data; that was just our projection to show how bad it might be.” [5]

I don’t think Longcore et al. [6] or the editors at Conservation Biology put much stock in the Wisconsin Study—so why continue to publish “projections” that have been so thoroughly discredited? Because doing so strengthens their case, at least among those who don’t know any better—especially people outside the scientific community, including many journalists, policy makers, judges, and the general public.

In their recent comment, Lepczyk et al. suggest that conservation biologists and wildlife ecologists “look to the evolutionary biology community” [1] for an example of how to influence policy:

“When local policies or regulations are put forth that promote the teaching of creationism or intelligent design, the evolutionary biologists have responded in force from across the nation and world.” [1]

Let’s set aside for the moment all the baggage associated with their analogy. My question is this: Is the evolutionary biology community still publishing bogus “projections” from 13 years ago? I doubt it.

Check Your Premises
In their recent paper (available for download via the American Bird Conservancy (ABC) website), Dauphiné and Cooper arrive at their absurd figure of “117–157 million free-ranging cats in the United States,” [7] in part, by way of Jessup’s “estimated 60 to 100 million feral and abandoned cats in the United States.” [3]

So where does Jessup’s figure come from? We have no idea—there’s no citation. And Jessup is no authority on the subject—having conducted no studies or reviews of studies that quantify the feral cat population. What’s more, his “estimation” is among the highest figures published. Yet this is the shaky foundation upon which Dauphiné and Cooper attempt to build their subsequent argument.

The authors then add to the (dubious) number of feral cats the proportion of pet cats allowed outdoors. They refer to a 2004 paper by Linda Winter, director of ABC’s Cats Indoors! campaign, in which it was reported, “A 1997 nationwide random telephone survey indicated that 66% of cat owners let their cats outdoors some or all of the time.” [8]

That’s an interesting way to put it—Winter makes it sound like two-thirds of pet cats are essentially outdoor cats. But the survey—commissioned by ABC!—actually indicates that “35% keep their cats indoors all of the time” and “31% keep them indoors mostly with some outside access.” [9] The difference in wording is subtle, and hampered by imprecision—it all comes down to the meaning of some.

Winter’s 2004 paper implies that there are twice as many outdoor pet cats as was indicated in the original survey—an interpretation Dauphiné and Cooper seem to embrace. Had they looked further—and to a less biased source—they might have been able to get a better handle on the degree of outdoor access. For example: a 2003 survey conducted by Clancy, Moore, and Bertone [10] revealing that nearly half of the cats with outdoor access were outside for two or fewer hours a day. And 29% were outdoors for less than an hour each day.

Do these “part-timers” have the same impact on wildlife as feral cats? Dauphiné and Cooper would have us believe they do.

[Note: For a closer look at the flaws in Dauphiné and Cooper’s paper, download “One Billion Birds,” by Laurie D. Goldstein.]

The lesson? Credible research begins with a solid foundation; a weak foundation—one plagued with unsubstantiated claims—on the other hand, leads to pseudoscience.

Or worse. ABC’s Senior Policy Advisor, Steve Holmer, cited Dauphiné and Cooper’s bogus numbers when he spoke to the Los Angeles Times about his organization’s involvement with the legal battle against TNR. It’s like the Wisconsin Study all over again.

When All Else Fails, Look It Up
Though this would seem to be utterly obvious, it apparently bears repeating: Don’t cite work you haven’t actually read.

Isn’t this emphasized in all graduate (indeed, undergraduate, too) programs? What grad student isn’t, at one time or another, tempted to take the easy way out—ride the coattails of somebody else who’s (presumably) done the real work? In addition to the ethical implications, such shortcuts tend to invite more immediate troubles, too. Again, George’s work (described above) provides an excellent case study. Below are some examples of how his work has been referenced in the cat predation literature:

“It is very unlikely that cats bring home all of the prey that they capture. What proportion they bring home has been little studied. George (1974) on a farm in Illinois USA found that three house cats, all adequately fed, brought home about 50% of the prey that they killed.” [11]

“George found that about 50% of prey were indeed brought home, with the other 50% being eaten, scavenged by other animals or simply not found.” [12]

“These approximations are probably underestimates, assuming that cats do not bring back all the prey that they kill.” [13]

Trouble is, George never said these things; what he said was:

“… the cats never ate or deposited prey where caught but instead carried it into a ‘delivery area,’ consisting of the house and lawn. The exclusive use of this delivery area was verified in 18 to 70 mammal captures per cat, as witnessed between early 1967 and 1971.” [2]

In 2000, Fitzgerald and Turner pointed out the fact that George’s work was being misrepresented, noting that the erroneous 50% figure “has been reported widely, though it is unfounded.” [14] Nevertheless, the myth persists—even in 2010.

“In Illinois, George (1974) found that only about half of animals killed by cats were provided to their owners, and in upstate New York, Kays and DeWan (2004) found that observed cat predation rates were 3.3 times higher than predation rates measured through prey returns to owners. Thus, predation rates measured through prey returns may represent one half to less than one third of what pet cats actually kill…” [7]

As Dauphiné and Cooper demonstrate, the “reinterpreted” version of George’s work makes for a very convenient multiplier—suddenly, every kill reported is doubled (or tripled, if Kays and DeWan are to be believed—and they’re not, but that’s a topic for another post). Never mind the fact that it has no basis in actual fact.

Getting a copy of George’s study isn’t difficult, especially with the inter-library loan services available today. To reference it—to use George’s work so that your own appears more credible—without ever having actually read it, is simply inexcusable. But citing it blindly suggests more than laziness—it points to a certain coziness that has no place in scientific discourse. Too much Kool-Aid drinking, and not enough honest research.

* * *

Scientists can (and do) look at identical results and come to very different conclusions. But misinterpreting, misrepresenting, or dismissing the conclusions of others, is something else altogether. As the above examples (and there are many, many more!) illustrate, this happens far too often in the feral cat/TNR literature. And if we can’t believe what researchers are saying about the work of others, why would we believe what they say about their own work?

Next, I’ll focus on some of the major flaws in the feral cat/TNR literature—beginning with small sample sizes…

References
1. Lepczyk, C.A., et al., “What Conservation Biologists Can Do to Counter Trap-Neuter-Return: Response to Longcore et al.” Conservation Biology. 2010. 24(2): p. 627-629.

2. George, W., “Domestic cats as predators and factors in winter shortages of raptor prey.” The Wilson Bulletin. 1974. 86(4): p. 384–396.

3. Jessup, D.A., “The welfare of feral cats and wildlife.” Journal of the American Veterinary Medical Association. 2004. 225(9): p. 1377-1383.

4. Guttilla, D.A. and Stapp, P., “Effects of sterilization on movements of feral cats at a wildland-urban interface.” Journal of Mammalogy. 2010. 91(2): p. 482-489.

5. Elliott, J., The Accused, in The Sonoma County Independent. 1994. p. 1, 10

6. Longcore, T., Rich, C., and Sullivan, L.M., “Critical Assessment of Claims Regarding Management of Feral Cats by Trap–Neuter–Return.” Conservation Biology. 2009. 23(4): p. 887–894.

8. Winter, L., “Trap-neuter-release programs: the reality and the impacts.” Journal of the American Veterinary Medical Association. 2004. 225(9): p. 1369-1376.

9. ABC, Human Attitudes and Behavior Regarding Cats. 1997, American Bird Conservancy: Washington, DC. http://www.abcbirds.org/abcprograms/policy/cats/materials/attitude.pdf

10. Clancy, E.A., Moore, A.S., and Bertone, E.R., “Evaluation of cat and owner characteristics and their relationships to outdoor access of owned cats.” Journal of the American Veterinary Medical Association. 2003. 222(11): p. 1541-1545.

11. Churcher, P.B. and Lawton, J.H., “Predation by domestic cats in an English village.” Journal of Zoology. 1987. 212(3): p. 439-455.

12. May, R.M., “Control of feline delinquency.” Nature. 1988. 332(March): p. 392-393.

13. Crooks, K.R. and Soule, M.E., “Mesopredator release and avifaunal extinctions in a fragmented system.” Nature. 1999. 400(6744): p. 563.

14. Fitzgerald, B.M. and Turner, D.C., Hunting Behaviour of domestic cats and their impact on prey populations, in The Domestic Cat: The biology of its behaviour, D.C. Turner and P.P.G. Bateson, Editors. 2000, Cambridge University Press: Cambridge, U.K.; New York. p. 151–175.

Hold Your Applause

20 May 2010•In the News, The Cat Debate

Three months after my letter to Conservation Biology was rejected, it’s become apparent what they were really looking for: applause, not criticism.

Of course it probably doesn’t help that I’m not a member of the club; I don’t even know the secret handshake. (Michael Hutchins, writing for the Wildlife Society Blog, “Making Tracks,” has accused me—an outsider—of trying to “out-science the scientists.”)

In April, Conservation Biology published a comment authored by Christopher A. Lepczyk, Nico Dauphiné, David M. Bird, Sheila Conant, Robert J. Cooper, David C. Duffy, Pamela Jo Hatley, Peter P. Marra, Elizabeth Stone, and Stanley A. Temple. The authors “applaud the recent essay by Longcore et al. (2009) in raising the awareness about trap-neuter-return (TNR) to the conservation community,” [1] and puzzle at the lack of TNR opposition among the larger scientific community.

The reasons behind this lack of opposition are unclear, but it may be that conservation biologists and wildlife ecologists believe the issue of feral cats has already been studied enough and that the work speaks for itself, suggesting that no further research is needed. Or, they simply do not want to devote time and energy to the issue and are unaware of policy actions.

I’d like to offer an alternative explanation. Yes, the work speaks for itself, but there are plenty of observers—surely, there are conservation biologists and wildlife ecologists among them—who don’t particularly like what it’s saying.

For the next few posts, then, I’m going to present a sampling of the more serious flaws—including exaggerated and misleading claims, botched analyses, questionable research and review methods, and widespread bias—all too common in the feral cat/TNR literature. Let’s see what Lepczyk at al. are cheering about…

References
1. Lepczyk, C.A., et al., “What Conservation Biologists Can Do to Counter Trap-Neuter-Return: Response to Longcore et al.” Conservation Biology. 2010. 24(2): p. 627-629.