The Things People Say (or Don’t)—Part 3

The American Bird Conservancy (ABC) is among the most visible organizations to oppose TNR—and put PR ahead of the relevant science (which ABC has been doing for years now).

ABC was one (along with the L.A. Audubon Society and Urban Wildlands Group) of several petitioners in the case that eventually led to an injunction against publicly supported TNR in Los Angeles. Following the court’s decision, ABC’s Senior Policy Advisor, Steve Holmer, told the Los Angeles 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.

Days later, I sent Holmer an e-mail, asking for details about his figure of 160 million feral cats (the number of birds killed could, I assumed, be addressed later). To his credit—and unlike the people I tried to contact at the Urban Wildlands Group and L.A. Audubon Society—Holmer actually replied, leading to a cordial but brief correspondence in which he directed me to the work of Nico Dauphiné and Robert J. Cooper.

Sure enough, just two pages into Dauphiné and Cooper’s article [1] (available for download via the ABC website):

There is therefore an estimated total of 117–157 million free-ranging cats in the United States.

But there are a number of significant problems with their estimate—which is calculated by combining an estimated number of feral cats with an estimated number of owned cats having outdoor access. Here, in a nutshell, is a breakdown of their calculation:

Dauphiné and Cooper start with 60–100 million “stray and feral (unsocialized) cats, nearly all of which range freely outdoors” a figure taken from a 2004 paper by David Jessup [2]. But, because Jessup didn’t cite his source(s), this is actually no estimate at all. At best, it’s a guess—and one intended to paint as stark a picture as possible.

Then, citing a 2004 paper (which in turn cites a study commissioned by ABC—the results of which are summarized here) by ABC’s Linda Winter [3], Dauphiné and Cooper suggest that “approximately 65%” of pet cats “are free-ranging outdoor cats for at least some portion of the day.” Taking 65% of 88 million—the number of pets cats estimated by the American Pet Products Association’s 2008 National Pet Owners Survey—the authors arrive at 57 million pet cats with outdoor access.

But what does that mean, to be free-ranging for at least some part of the day?

A 2003 survey conducted by Clancy, Moore, and Bertone [4] suggested 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. And a closer look at the study commissioned by ABC  indicates similar behavior: “35% keep their cats indoors all of the time” and “31% keep them indoors mostly with some outside access.” [5]

For Dauphiné and Cooper, though, these cats are no different from feral cats. For them to simply add the number of “part-time” outdoor cats to the population of “free-ranging outdoor cats” is highly misleading! The authors have no idea what impact these cats might have on bird populations—which is the stated purpose of their paper.

Note: For a closer look at the flaws in Dauphiné and Cooper’s paper, download “One Million Birds,” by Laurie D. Goldstein.

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OK, back to Steve Holmer and the L.A. Times

Holmer’s estimate of 160 million is not a range, but the high limit of a seriously-flawed estimate (which is itself based on little more than wild guesses). And he refers specifically to feral cats—an error even Jessup, Dauphiné, and Cooper (none of whom, it seems, is likely to give feral cats even the slightest benefit of the doubt) don’t make.

Given the context of the discussion—TNR in Los Angeles—such an error was likely (perhaps intended?) to have serious consequences. To suggest that there are 160 million feral cats in this country—approximately one feral cat for every two human inhabitants—is irresponsible and manipulative. And it raises doubts about the integrity of ABC and its representatives. All of which I told Holmer. His reply read, in part:

We are doing are [sic] best to convey the facts as they become available. The 160 million figure was based on an earlier version of Nico’s latest paper and are now being updated in our materials which should now say:

There are currently 88 million pet cats in the U.S. according to a pet trade association, and that number is growing. In addition, it is estimated that there may be 60–100 million free-ranging feral cats in the U.S., and that these cats may collectively kill more than one million birds each day. Reducing this mortality even a small amount could potentially save millions of birds each year.

I haven’t checked the ABC website to verify Holmer’s claim. In any event, the damage was already done; ABC and the other petitioners had put a stop to publicly supported TNR in Los Angeles. And, from what I’ve seen (I’ve yet to wade through the thousands of pages of discovery documents in the case), they’d done so by selectively overlooking, ignoring, and misrepresenting the scientific research. Or, in the case of Holmer’s comment to the Times, simply “inventing” it.

By the way, I asked Holmer about his revised figure of “more than one million birds each day” killed by cats. He’s stopped replying to my e-mail.

1. 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

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

3. Winter, L., “Trap-neuter-release programs: the reality and the impacts.” Journal of the American Veterinary Medical Association. 2004. 225(9): p. 1369-1376.

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

5. ABC. (1997). Human Attitudes and Behavior Regarding Cats. Washington, DC: American Bird Conservancy. Available at: