Many Loose and Ill-considered Statements

Does the U.S. Fish and Wildlife Service have an official policy on free-roaming cats and TNR? The official word from the agency is no. But that hasn’t stopped Service employees around the country from suggesting otherwise.


Had you attended the Southeast Partners in Flight conference in February, you would, more than likely, have come away with the impression that the U.S. Fish and Wildlife Service has—despite statements to the contrary—an official, science-based position on free-roaming cats and TNR.

In his presentation Feral and Free-ranging Cats and Urban Birds, Steve Holzman, South Atlantic Geographic Area Data Manager for USFWS, argued that if the goal of PIF is to “keep common birds common,” predation by cats simply can’t be ignored. Among the “next steps” Holman proposed: “Continued work on USFWS position statement on feral and free-ranging cats, and zero tolerance on all federal lands, especially parks and refuges,” and “State policies that advocate trap and remove for all state lands.”

Hinting at what an uphill battle such policies face, Holzman pointed out that cats “are very popular,” and “currently represent 87.3 percent of all Internet content.”

This last bit was delivered as a humorous aside,” notes Holzman in the endnotes of his revised presentation. “No one really knows what percentage of Internet content is related to cats.”

I’ll have to take Holzman at his word about this being a joke, as I wasn’t there.

But what about those very official-sounding policy proposals? Surely, the audience took that stuff seriously. And yet, those bullet points were purged in his recent round of edits—prompted by a lengthy e-mail I sent to Holzman. (“Your questions have led me to understand the need to revise the PowerPoint presented on the SEPIF website,” Holzman wrote.)

What’s going on here?

“I have a personal interest in this issue,” Holzman explained to me in his reply, “and my presentation was based solely on my own individual research through published literature and standard web-based resources.”

“My position with the Fish and Wildlife Service’s Southeast Region is Regional Refuge Inventory and Monitoring Data Manager. I was not presenting as the Service’s expert on this issue and the information I provided does not reflect an agency position.”

I’ll get to some of Holzman’s “individual research” shortly. (At which time readers may wish to find a comfortable chair. Maybe grab a stiff drink.) Like many of his edits, Holzman’s response to my inquiry raises as many questions as it answers—beginning with these two:

  • If Holzman’s presentation didn’t “reflect an agency position,” then why did the opening slide identify him as an employee of USFWS? Why, under the circumstances, would attendees think his presentation didn’t reflect an official position? (In the revised version, Holzman’s affiliation is “Georgia Ornithological Society,” for which he served, until recently, as Conservation Chair.)
  • Why, if Holzman was truly “off the clock,” did he weigh in on USFWS policy? Again, the audience had every reason to believe his presence at the conference was in some official capacity—an impression unchanged, of course, by revisions made months after the fact.

If all of this sounds familiar, that’s because USFWS has been trying for months now to deny the existence of a policy on free-roaming cats—all the while indicating elsewhere that such a policy is, if not quite finalized, well underway.

Last September, the Service raised eyebrows with the announcement of its workshop Influencing Local Scale Feral Cat Trap-Neuter-Release Decisions, to be held in conjunction with The Wildlife Society’s annual conference. The subsequent backlash—including an action alert by Best Friends—was enough to prompt USFWS to address the “many expressions of interest and concern” on its Open Spaces blog].

If the agency’s response was less than persuasive, it was in part due to their decision to make wildlife biologist Tom Will one of the workshop facilitators.

In January 2010, Will made a presentation (What Can Federal Agencies Do? Policy Options to Address Cat Impacts to Birds and Their Habitats) to the Bird Conservation Alliance in which he described free-roaming cats as a “contentious, complex, rapidly proliferating problem,” and then outlined in some detail possible USFWS responses.

As with Holzman’s presentation (billed in the SEPIF conference agenda (PDF) as “Feral Cats/TNR Overview—History/Policy/Strategic Actions”) two years later, it’s difficult to imagine Will’s BCA audience coming away with the impression that USFWS had no free-roaming cat policy in the works. It’s right there in Will’s title!

The two presentations have something else in common: both are plagued with errors, misrepresentations, and glaring omissions when it comes to the relevant science.

I picked apart Will’s a year ago; now it’s Holzman’s turn.

Predation
Among the studies Holzman cites to support his assertion (implied more than anything, I suppose) that predation by cats is related to declining bird populations is Cole Hawkins’ PhD work in two northern California parks (which I critiqued in one of my first posts).

“The preference of ground feeding birds for the no-cat treatment was striking,” observed Hawkins. “For ex­ample, California quail were seen almost daily in the no-cat area, whereas they were never seen in the cat area.” [1] But Hawkins ignores almost entirely the fact that five of the nine ground-feeding species included in his study showed no preference for either area. If these birds were just as vulnerable as, say, the quail, then why did they remain so close the cats?

Indeed, Hawkins’ scat analysis suggests that predation on birds is minimal: just 4 percent of 120 scats contained feathers.

Even extensive predation doesn’t necessarily lead to population-level impacts. In their contribution to The Domestic Cat: The Biology of Its Behaviour, researchers Mike Fitzgerald and Dennis Turner thoroughly reviewed 61 predation studies, concluding rather unambiguously:

“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.” [2]

Now, Holzman also cites a 2005 paper by Baker et al. in which the authors do warn, based on their results of a large survey of households in Bristol, UK, that “estimated predation rates were high relative to annual productivity, such that predation by cats may have created a dispersal sink for juveniles from more productive neighbouring areas.” [3]

But this work was just a pilot study. Subsequent research at the site (which Holman conveniently fails to mention), in which the researchers “compared the condition of those birds killed by cats versus those killed in collisions,” revealed that cat-killed birds “were likely to have had poor long-term survival prospects.” [4] (I described both studies in detail in a June 2010 post.) In fact, these results weren’t entirely unexpected; other researchers applying similar methods have come to essentially the same conclusion: that birds killed by cats “often have a poor health status.” [5]

It’s a point the Royal Society for the Protection of Birds makes using refreshingly straightforward language: “Despite the large numbers of birds killed, there is no scientific evidence that predation by cats in gardens is having any impact on bird populations UK-wide…”

“It is likely that most of the birds killed by cats would have died anyway from other causes before the next breeding season, so cats are unlikely to have a major impact on populations” [6].

The fact that none of this well-documented work found its way into Holzman’s presentation is hardly surprising, as it seems he’s getting most of his information from the American Bird Conservancy and The Wildlife Society—neither of which has demonstrated the slightest interest in an honest debate about the impacts of free-roaming cats.

Population Dynamics
Holzman claims that the population of stray and feral cat is increasing due to “their perpetuation in colonies… Feeding stations can now be found behind hotels, fast food restaurants and strip malls.” (Slide  8 )

It is, explains Holzman, “basic biology”: an increase in resources leads to an increase in population.

Imaginary Numbers
Interestingly, the sole source Holzman cites—the abstract of Christopher Lepczyk’s presentation to the 126th Stated Meeting of the American Ornithologists’ Union—has little to offer by way of support. The closest Lepczyk comes, in fact, is his observation that “the number of cats in the U.S. has tripled over the past 40 years, from approximately 30 million to 90 million.”

But those are pet cats. And, as multiple surveys have demonstrated, people are increasingly keeping these cats indoors. [7–9]. In fact, it’s entirely likely that this trend has largely offset the rise in ownership numbers.

As for the population of stray and feral cats, neither Holzman nor Lepczyk provides any evidence of an upward trend. Animal People editor Merritt Clifton, by contrast, has suggested that “the feral cat population had probably peaked in 1993 or 1994 before beginning a downward trend.”

“After a decade of intensive TNR in much of the country, 40 million is now very close to being the upper-end plausible estimate of all free-roaming cats in the U.S., including both pets and ferals, and then only at the height of ‘kitten season,’ when about half of the total feral cat population are still too young to hunt, with approximately a 50 percent chance of living long enough to ever hunt successfully.” [10]

But Holzman’s not the only TNR opponent to claim, without evidence, that the number of community cats is on the rise. Indeed, it’s become a popular talking point.

In February, ABC president George Fenwick, told the Akron Beacon Journal: “Our read is really quite clear that free-roaming cats—that includes TNR cats—are proliferating. They are expanding horrifically…” Fenwick’s evidence? If he had any, I think he’d use his many opportunities with the media (generally incapable of even the most obvious follow-up question) to go into some details.

He doesn’t go into details because he doesn’t have any “clear read.”

In one of his three comments on an L.A. Times story about the recent case of typhus reported in Santa Ana, TWS CEO/executive director Michael Hutchins describes feral cats as “a growing problem nationwide as more and more municipalities are going to no kill shelters and trap-neuter-release management… puts more and more cats out into the environment.”

His evidence of the “growing problem”? Like Fenwick and Holzman, he apparently doesn’t feel the slightest obligation to produce any.

Basic Biology
Holzman’s “basic biology” argument is another one that seems to be gaining in popularity—why not? It’s short and sweet, and sounds perfectly plausible. But where are the studies demonstrating a straightforward causal connection between feeding and population increases? That’s another story.

Indeed, researchers in Brooklyn found no such link, noting that “supplemental feeding” had no “significant effect on population density,” because available food supplies—mostly garbage—already exceeded what the cats required. [11]

What’s more, it’s been well documented on uninhabited islands from which cats have been eradicated that populations of feral cats can increase without any handouts at all. [12–14]

If it’s really just “basic biology,” why isn’t Holzman promoting more bird feeding? After all, increased resources will increase their numbers, right? (You’re welcome, Steve.)

A Brief Sidenote: Perpetuating Myths
Holzman cites Lepczyk’s AOU conference abstract three separate times (this in addition to one citation of the widely-circulated paper describing Lepczyk’s PhD work). That’s not a particularly strong bit of “evidence,” the abstract of a conference presentation. Worse, there’s virtually nothing in Lepczyk’s abstract to support Holzman’s claims. Other than perhaps these two sentences:

“While debate remains about the exact degree to which outdoor domestic cat (Felis catus) predation impacts individual bird species, it is nonetheless a major source of avian mortality. Specifically, cats are opportunistic and indiscriminate predators that must consume 5–8 percent of their body mass in animal matter every day, with birds representing about a quarter to [sic] third of the diet.”

Really? Birds represent about a quarter to a third of the diet of the outdoor domestic cat? I’ll bet that got the attention of AOU attendees!

Trouble is—for those of us who care about such things—it’s simply not true.

The original source for Lepczyk’s whopper would seem to be ABC’s brochure, Domestic Cat Predation on Birds and Other Wildlife (PDF), which claims: “extensive studies of the feeding habits of domestic, free-roaming cats… show that approximately… 20 to 30 percent [of their diet] are birds.” [15]

Ellen Perry Berkeley carefully examined—and debunked—this nonsense in her 2004 book, TNR Past Present and Future: A history of the trap-neuter-return movement, pointing out that ABC’s figure (among its many flaws) is actually based largely on a misreading and/or misrepresentation of Mike Fitzgerald’s considerable research into the dietary habits of cats. (Fitzgerald reported results as percent frequency of occurrence, not as a percentage of overall dietary intake. In other words, bird remains were found in the scat or stomach contents of about 21 percent of cats studied.)

ABC’s “interpretation,” suggests Fitzgerald in his communication with Berkeley, likely overstates predation by a factor of two or three. [16]

One wonders whether Lepczyk mislead his audience intentionally or out of ignorance. Either way, his claim raises serious questions about his credibility on a subject about which he routinely writes and lectures. (Equally worrisome is the deafening silence that generally accompanies such inexcusable behavior.)

Problems with TNR
Holzman suggests that the R in TNR stands for Release, Return, or Re-abandon, “depending on your stance.” This far into his presentation—Slide 16 of 26 in the revised version—we know perfectly well which terms Holzman prefers.

Lest there be any confusion, though, Holzman included the following two slides in his original presentation. (It’s ironic that such sharp commentary was acceptable in the “USFWS” version, but didn’t make the cut for the “personal interest” version.)

Abandonment
To support his claim that “colonies attract continued abandonment,” Holzman—like virtually every other TNR opponent I’ve seen raise the subject—turns to a 2003 paper by Daniel Castillo and Alice Clarke. “On several occasions,” observe the authors, “we witnessed people abandoning unwanted cats. Additionally, numerous kittens and females with litters were also abandoned at the parks.” [17]

Any TNR program contends with the unfortunate (and illegal) dumping of cats. Even so, 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—however weak—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 potential impacts to wildlife and the environment).

Predation (Again)
TNR “does not stop predation,” claims Holzman. “Well-fed cats still hunt.” This, of course, is one of the most common complaints of TNR opponents—who, more often than not, prefer to leave it at that, ignoring context entirely. The health status of the birds caught by cats, for example, as described previously.

Or, the rather unique context of a sterilized colony of managed cats.

The only study I know of that investigated this in detail found minimal predation among such cats. Indeed, over the course of approximately 300 hours of observation (this, in addition to what Castillo and Clarke (the very same researchers whose work Holzman cites elsewhere) described as “several months identifying, describing, and photographing each of the cats living in the colonies” prior to beginning their research), researchers “saw cats kill a juvenile common yellowthroat and a blue jay. Cats also caught and ate green anoles, bark anoles, and brown anoles… [and the researchers] found the carcasses of a gray catbird and a juvenile opossum in the feeding area.” [17]

There were, at any one time, 85–95 cats across the two study sites—ample opportunity for documenting “well-fed cats” on the hunt—and this was all the predation that was observed?

Like most of Holzman’s talking points, this one simply doesn’t stand up to careful scrutiny.

Feeding and Breeding
Holzman provides no support for his assertion that “feeding 365 days increases fecundity of unneutered individuals.” (Slide 18) Indeed, I know of no such evidence—and we’ve already been through his “basic biology” argument.

Interestingly, Clifton (himself opposed to feeding, as he explained via e-mail: “There is no need—none—to provide supplemental feeding, except to periodically count the cats.”) argues: “Nearly seven centuries of killing cats doubled the fecundity of the species.” [10, emphasis mine]

Funny how TNR opponents never acknowledge this point.

Nuisance Complaints
TNR, claims Holzman, “doesn’t stop unpleasant behaviors resulting in complaints from neighbors.” (Slide 17) As evidence, he once again cites Hawkins’ PhD work and Lepczyk’s AOU abstract—neither of which is relevant. And, although Linda Lord’s 2008 paper, also cited as support, does “characterize attitudes toward and perceptions of free-roaming cats among individuals living in Ohio,” [8] there are no specific references to nuisance complaints.

Indeed, the only possibly relevant source Holzman cites is a widely-circulated 2004 paper by Linda Winter, then director of ABC’s Cats Indoors! program. “In response to complaints from citizens about numerous stray and feral cats,” writes Winter, “the Akron City Council passed an ordinance on March 25, 2002, prohibiting domestic cats from running at large… If the public did not support this program, far fewer cats would have been trapped because private citizens did most of the trapping.” [18]

But Winter’s account of Akron’s support for the ordinance (and its subsequent “success”) was, as I found out a year ago when I dug into it, largely fictional.

Just about anybody who’s ever had a cat—indoor, outdoor, “tame,” or “feral”—will tell you: in the vast majority of cases, the “unpleasant behaviors” Holzman refers to either disappear entirely or are at least reduced significantly. The fact that Holzman says otherwise suggests that he may not actually be familiar with real-world TNR at all.

Or, as it turns out, much of the literature on the subject, either.

“Neutering … alters certain behaviors,” explain Kathy Hughes and Margaret Slater, in their 2002 paper describing Texas A&M’s TNR program, “making cats less likely to roam, spray, and fight, [19] further lessening the risk of spreading disease as well as decreasing nuisance complaints.” [20]

A TNR program “used to control a colony of cats residing in abandoned garages in London,” for example, resulted in “complaints about the cats [being] virtually eliminated.” [21, as cited in 21] On the University of Central Florida campus, “free-roaming cats were considered by campus authorities to constitute a nuisance” prior to implementation of “a TNR program with adoption.” [22] The TNR program on the Texas A&M campus led to a decrease in “the number of cat complaints received by the university’s pest control service.” [20]

And, a study on five campuses of the University of KwaZulu-Natal, South Africa, found that “nuisance complaints (18 percent) … came from the low-maintenance sites that had no feeding programs.” [23]

Holzman, I suppose (for reasons that will become clear shortly), would dismiss these findings outright, however—attributing them to pro-TNR researcher bias.

Success of Lethal Control Methods
Among the examples Holzman cites as “trap-and-remove success stories,” are Saddle Creek Park (Polk County, FL) and the Gilbert Riparian Preserve in Arizona. (Slide 20)

I’ve spoken with people familiar with both locations and am told emphatically that cats remain and/or continue to appear at these sites—suggesting that “success” in this case means a policy that allows for, or requires, ongoing removal (which, as Holzman acknowledges elsewhere in his presentation, typically results in the killing of cats).

I doubt the SEPIF audience got the message, though. It’s far more likely that they understood “success” to mean a one-time “removal.” That approach might work on an island. Of course, Holzman isn’t likely to use island eradications as success stories, as they tend to be time-consuming, incredibly expensive, and horrifically inhumane.

•     •     •

Birds of a Feather
If nothing else, Holzman is remarkably consistent when it comes to his position on free-roaming cats and TNR. Whether as chair of the GOS’s Conservation Committee, or as USFWS Southeast Region Regional Refuge Inventory and Monitoring Data Manager, he sticks to the official, approved talking points.

All of which might explain why Holzman was among those former Smithsonian Migratory Bird Center researcher Nico Dauphiné thanked “for helpful information, advice, ideas, and discussion in researching [the] subject” [24] in her often-cited 2009 paper. Two years later, she quoted him in her contribution to The Impact of Free Ranging Cats, a special section of The Wildlife Professional’s Spring issue.

“There was a massive public outcry when people witnessed the effects of the recent Deepwater Horizon oil spill on birds in the Gulf of Mexico,” says Steve Holzman, a U.S. Fish and Wildlife Service (FWS) biologist who helped with disaster response. “Yet cats across the U.S. kill more than one million birds in a single day, which is far more than all of the birds killed in the worst oil spill in U.S. history.” [25]

(“Where is the outrage over such slaughter?” Dauphiné asked rhetorically. Later, on the stand defending herself against charges of attempted animal cruelty, she backpedaled: “That’s—yeah, those were the editor’s words, not mine.” [26])

The Great Appeal of Lethal Control Methods
In December 2011, Holzman sent a letter to Kathy Mooneyham, director of DeKalb County (GA) Animal Services, and the DeKalb Board of Commissioners after Best Friends Animal Society brought its Feral Freedom program to DeKalb County.

“I am concerned that your change in official policy may have been done without Board approval or public hearings,” wrote Holzman. In fact, his concern apparently had very little to do with procedures and protocols, and everything to do with—not surprisingly—the practice of TNR. Among his litany of complaints (echoed—again, not surprisingly—in the GOS’s Position Statement: Managing Feral and Free-ranging Domestic Cats): “conflicts” surrounding “private property boundaries,” the public health threats posed by free-roaming cats (e.g., rabies and toxoplasmosis), and the “feeding 365 days per year,” which results, invariably, in “increased fecundity.”

“One could argue (and PETA has) that TNR is not humane to the cat that will eventually die from a myriad of sources that kill much less humanely than euthanasia,” writes Holzman. “I consider TNR an abandonment of our role as stewards of domestic animals.”

Good stewards—according to the Holzman/PETA/TWS doctrine, at least—round up and kill domestic animals. By the millions, if necessary. (As soon as I get this posted, I’m going to look up steward in the dictionary.)

In his letter, Holzman describes TNR as “a controversial policy,” whereas: “Removal is non-controversial and has worked in many areas.”

Non-controversial?

There was certainly controversy over the “removal” of cats from the Gilbert Riparian and Saddle Creek Park, two of the “success stories” Holzman cites in his SEPIF presentation. And, as I’ve already pointed out, other cats continue to move into these locations (to the surprise of nobody familiar with the issue).

And what about the backlash earlier this year when Loews Hotels announced they would be trapping cats on their Orlando properties? Or, earlier this month, when cats were to be rounded up in Santa Ana, CA, blamed (without any substantive cause, apparently) for a case of typhus?

Non-controversial? Effective?

Wishful thinking on both counts.

The Crisis in Education
Holzman closes his letter insisting “that there is no scientific evidence (produced by an unbiased researcher) that TNR reduces the overall population of feral cats in a county or city.”

“All the research that shows reductions were conducted by TNR advocates and even then only shows reduction at the colony level and even that is qualified. The removal of friendly cats and kittens probably causes any reduction in colony size” (his emphasis, not mine).

He then suggests that Mooneyham and the BOC download Travis Longcore’s paper [27] from the ABC website “to educate [themselves] on this controversial subject.”

•     •     •

Early in his SEPIF presentation, Holzman includes—for reasons I don’t quite understand—a quote from Edward Howe Forbush’s 1916 book Domestic Cat: Bird Killer, Mouser and Destroyer of Wildlife.

“Medical men, game protectors and bird lovers call on legislators to enact restrictive laws. Then ardent cat lovers rouse themselves for combat. In the excitement of partisanship many loose and ill-considered statements are made.” [28]

As Domestic Cat makes clear, Forbush, Massachusetts’ state ornithologist, was himself a rather generous source of such statements. But, “much of Forbush’s antipathy toward cats,” suggests Clifton, in an Animal People story published early last year, “might be ascribed to the context of the times.”

“His life coincided with the era in which New England wildlife was more depleted than at any time since. Logging, ploughing, damming, and unrestrained development depleted the forest cover, the grasslands, and the rivers. Precocious as Forbush was in his birding, which then was done chiefly with a shotgun, predatory mammals, fur-bearers, and most wild species considered edible had already been extirpated from most of Massachusetts before he had much chance to see or kill them.” [29]

Clearly much has changed since Forbush’s day. And yet, nearly 100 years later, much remains the same: the “excitement of partisanship,” as Steve Holzman’s SEPIF presentation demonstrates, is still the cause of “many loose and ill-considered statements.”

Literature Cited
1. 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.

2. 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.

3. 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. http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2907.2005.00071.x/abstract

4. 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

5. 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/

6. RSPB (2011) Are cats causing bird declines? http://www.rspb.org.uk/advice/gardening/unwantedvisitors/cats/birddeclines.aspx Accessed October 26, 2011.

7. 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

8. 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

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

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

11. 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

12. 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

13. 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

14. 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

15. ABC, Domestic Cat Predation on Birds and Other Wildlife. 2011, American Bird Conservancy: The Plains, VA. http://www.abcbirds.org/abcprograms/policy/cats/materials/CatPredation2011.pdf

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

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. Winter, L., “Trap-neuter-release programs: The reality and the impacts.” Journal of the American Veterinary Medical Association. 2004. 225(9): p. 1369–1376. http://avmajournals.avma.org/doi/abs/10.2460/javma.2004.225.1369

http://www.avma.org/avmacollections/feral_cats/javma_225_9_1369.pdf

19. Mahlow, J.C. and Slater, M.R., “Current issues in the control of stray and feral cats.” Journal of the American Veterinary Medical Association. 1996. 209: p. 2016–2020.

20. Hughes, K.L. and Slater, M.R., “Implementation of a Feral Cat Management Program on a University Campus.” Journal of Applied Animal Welfare Science. 2002. 5(1): p. 15–28. http://login.ezproxy1.lib.asu.edu/login?url=http://search.ebscohost.com/login.aspx?direct=true&db=aph&AN=6590371&site=ehost-live

21. Neville, P.F., Feral Cats: Management of Urban Populations and Pest Problems by Neutering., in Mammals as Pests, R.J. Putnam, Editor. 1989, Chapman & Hall: London. p. 261–267.

22. Levy, J.K., Gale, D.W., and Gale, L.A., “Evaluation of the effect of a long-term trap-neuter-return and adoption program on a free-roaming cat population.” Journal of the American Veterinary Medical Association. 2003. 222(1): p. 42-46. http://avmajournals.avma.org/doi/abs/10.2460/javma.2003.222.42

23. Jones, A.L. and Downs, C.T., “Managing Feral Cats on a University’s Campuses: How Many Are There and Is Sterilization Having an Effect? Journal of Applied Animal Welfare Science. 2011. 14(4): p. 304–320.

24. 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

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

26. Mullins, L., “Apocalypse Meow.” Washingtonian. 2012. April. p. 60–65, 167–170. http://www.washingtonian.com/articles/people/apocalypse-meow/

27. 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

28. Forbush, E.H., The Domestic Cat: Bird Killer, Mouser and Destroyer of Wild Life; Means of Utilizing and Controlling It 1916, Boston: Wright and Potter Printing Company.

29. Clifton, M. (2011, January/February). The Domestic Cat: Bird Killer, Mouser and Destroyer of Wild Life; Means of Utilizing and Controlling It, by Edward Howe Forbush. Animal People, p. 17, from http://www.animalpeoplenews.org/11/1/Jan-Feb2011.zip%20Folder/Ho8j3PWe.html

http://www.animalpeoplenews.org/11/1/Jan-Feb2011.pdf

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