Revisiting “Reassessment”

5 Jan 2011

“Reassessment: A Closer Look at ‘Critical Assessment of Claims Regarding Management of Feral Cats by Trap-Neuter-Return’” has been revised and expanded!

This paper, a brief review and critique of the essay “Critical Assessment of Claims Regarding Management of Feral Cats by Trap-Neuter-Return” by Travis Longcore, Catherine Rich, and Lauren M. Sullivan, now includes sections on Toxoplasma gondii, the mesopredator release phenomenon, and more. In addition, links and downloadable PDFs have been added to the list of references.

Over the past year, “Critical Assessment” has gotten a great deal of traction among TNR opponents, despite its glaring omissions, blatant misrepresentations, and obvious bias. “Reassessment”—intended to be a resource for a broad audience, including, wildlife and animal control professionals, policymakers, and the general public—shines a bright spotlight on these shortcomings, thereby bringing the key issues back into focus.

Act Locally
Politics is, as they say, local. This is certainly true of the debate surrounding TNR. Policies endorsing TNR, the feeding of feral cats, etc. typically begin with “Town Hall” meetings, or even meetings of neighborhood associations. “Reassessment” provides interested parties with a rigorous, science-based counter-argument to those using “Critical Assessment” as a weapon against feral cats/TNR.

So, once you’ve had a look for yourself, please share generously! Together, we can—in keeping with the mission of Vox Felina—improve the lives of feral cats through a more informed, conscientious discussion of feral cat issues in general, and TNR in particular.

Download PDF

False Confessions

12 Aug 2010

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 4: Mean Spirited

4 Jun 2010

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 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 1: Lost in Translation

24 May 2010

“…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.