The Science of Sustainability

Culture Clash: Of Cats, Birds and Conservation

  • share this article
  • Facebook
  • Email
domestic house cat

Domestic bliss: Born under a bush in Guerneville, this once feral cat now enjoys the comforts of home. Patience, dedication, and gentle handling can transform a frightened, suspicious feral cat into a trusting, loving companion. (Photo: Barry Bergman)

We humans have an uneasy relationship with nature. Lest you doubt it, consider that the 1964 Wilderness Act defines wilderness as “an area where the earth and community of life are untrammeled by man, where man himself is a visitor who does not remain.”

The notion that people live apart from nature might explain our sometimes skewed views of wildlife—Americans keep as many as 20,000 tigers, cheetahs, and other big cats as pets—and our seemingly unique capacity for destroying natural resources.

By recent estimates, we’re using resources 50 percent faster than they can recover. Despite mounting evidence linking human well-being to healthy ecosystems, we seem constitutionally incapable of changing our behavior.

Conservation biologists try to inspire people to act in environmentally-friendly ways, but often inspire emotional confrontations instead. That’s why some biologists are looking to social psychologists for advice.

Conservation Psychology
It’s no surprise that conflicts arise when two groups view the facts of a situation through a different lens. But the hope is that understanding the social roots of conservation conflicts—how people’s values and beliefs shape their behavior—will suggest strategies for resolving them.

In a study published earlier this month researchers led by Nils Peterson at North Carolina State University applied this approach to a particularly contentious issue: feral cats and their impacts on birds.

Feral cats are simply house cats that, without the care and love of an owner, behave like a wild animal. And it’s hard to imagine a group more emotionally invested in an issue than the women who take care of feral cats. (I should know. I once looked after a mini-colony in the backyard of my Sunset District rental.) As several studies show, cat colony caretakers tend to be women, many of whom also have tame cats at home, see their feral charges as pets, and often cite sympathy, ethical concerns, and love of animals as their main motivators.

feral cat colony

This feral cat colony lives in an Arrow Rock, Missouri, backyard and neighboring grounds. (Photo: Scott Granneman, St. Louis, MO)

No one knows how many feral cats live in the U.S., though the American Veterinary Medical Association suspects the number rivals that of cats living as pets, estimated at 86 million.

By most accounts, feral cats face a miserable life. One study looking at reproductive rates in feral cats found that 75% of kittens died or disappeared within six months. Most were either run over by cars or killed by stray dogs. Feral cats have twice the rate of FIV of house cats and significantly higher rates of bacterial and parasitic infections.

It’s understandable why kind-hearted people take care of cats left to fend for themselves. Unfortunately, these natural-born killers are doing what comes naturally. And wildlife populations, including species common and rare, are paying for our good intentions.

Study after study documents the toll feral cats take on wildlife. Most experts think the cats kill hundreds of millions of native birds, mammals, reptiles, amphibians, and fish in the U.S. each year. Wildlife rehabilitation specialists at Walnut Creek’s Lindsey Museum handled more than 1,000 birds with cat-related injuries in 2003 alone. Of course, no one knows how many birds died in backyards or wound up in cats’ bellies.

Some advocates say feeding cats controls their predatory instincts, but the evidence suggests otherwise. A 1999 study of two East Bay parks found that in sites with regularly fed cat colonies, “native birds were markedly less abundant and less likely to nest, and ground-foraging species such as California quail and thrasher were entirely absent.” Feral cats also endanger native raptors by depleting their prey base.

Polarized Views
Against this background, Peterson and his team polled 338 cat colony caretakers and 239 bird conservation professionals (from the Audubon Society, American Bird Conservancy, and similar groups) about their views of feral felines, the cats’ impacts on wildlife, and strategies to control their populations. Many feral cat advocates promote the use of trap-neuter-and-return programs to control colonies, though studies fail to support their effectiveness. That’s probably partly because people abandon their animals faster than caretakers can sterilize them.

Not surprisingly, the two groups held opposite views on nearly every question. “Bird people” viewed feral cats as “pests” and considered “euthanasia” an appropriate management strategy. Just 20% of “cat people” thought feral cats endanger native birds and just 6% thought feral cats carry disease.

African wildcat

Genetic studies trace the origins of the house cat to at least five wildcat species (Felis silvestris), originating in the Near East. The African Wild Cat (Felis silvestris lybica), above, is the house cat's most recent ancestor in the history of domestication. (Photo: Sonelle, Johannesburg Zoo, South Africa)

For the record, feral cats can transmit rabies and numerous other diseases to wildlife, either indirectly—for example, when feces-borne parasites enter the watershed and infect otters and other marine life—or directly, by spreading FIV to mountain lions and critically endangered Florida panthers who prey on them.

A surprising 59% of caretakers thought feral cats play a natural role as predators. That was true for their progenitors, Near East wildcats (Felis silvestris lybica), which started hanging around farmers and their rodent-infested grain silos in the Fertile Crescent some 10,000 years ago. (Experts think, given the cat's notorious independent nature, domestication happened as cats adopted people rather than vice versa.) But domestication released these felines from the constraints of natural selection and paved the way for a new species, Felis catus, thousands of years ago.

A Path to Compromise
With little common ground between bird people and cat lovers, whose positions are so tied to personal views of the problem, public education campaigns probably won’t work, the researchers say. Feral cat advocates care passionately about the welfare of individual cats while bird conservation workers (and wildlife biologists) care about the long-term prospects of wildlife populations.

kitty cam and injured bird

The "kitty cam" outfitted on a house cat as part of a research project shows an injured phoebe. Sixty pet cats in Athens-Clarke County, Georgia, wore cameras for 7 to 10 days on their outdoor adventures. The research is a joint project of the University of Georgia and National Geographic. (Photo: University of Georgia)

What might help is engaging cat caretakers in research on feral cat behavior—it’s hard to deny what you see with our own eyes—as well as in programs to protect wildlife. Plus, as other studies show, the best solutions will likely be site specific. Where birds and other wildlife populations are in decline, a more aggressive control strategy might be called for. But in healthier ecosystems or areas that harbor smaller colonies, trap-neuter-and-return might be a reasonable solution.

Some think an even better solution might be housing cats in enclosed sanctuaries, like Belleglen Sanctuary in Chico, which protects wildlife while keeping feral cats safe from disease and injury. But such shelters quickly fill to capacity.

Even though the survey found highly polarized opinions, it also showed that both groups share a love of animals—many “bird people” owned cats and many “cat people” said they love birds too. What’s more, caretakers were optimistic that they could work with biologists to find better ways to manage feral cats.

With one in eight bird species threatened with extinction, this is an opportunity for collaboration we can’t afford to squander.

There’s one thing no one disputes. The kind souls who take care of feral cats didn’t create the problem. People who abandon the animals that depend on them did. It’s illegal to abandon your pet in most states, including California, but enforcement is notoriously difficult. Clearly, we need new strategies to stop this cruel and inhumane behavior.

All the cats I’ve ever adopted were once stray or feral. It takes time, effort, and patience to socialize a feral cat, but there’s nothing like watching mistrust turn to affection. I love to watch the vestigial gestures of wild felids in my house cats, but I know they didn’t evolve as natural predators on the American landscape. They depend on us for food, shelter, and safety. Animal shelters take in 6 million to 8 million cats and dogs each year and euthanize about half of them. We have an ethical duty to take better care of our animals—domesticated and wild—and learn to tell the difference.

Related

Explore: , , , , , ,

Category: Biodiversity, Biology, Blog, Environment

  • share this article
  • Facebook
  • Email
Liza Gross

About the Author ()

Liza Gross, a freelance science writer and senior editor at the biomedical journal PLOS Biology, channeled an early love of wildlife into a lifelong exploration of the numerous ways diverse species, including humans, interact in the natural world. She writes mostly about wildlife, conservation, and environmental health. Her stories reflect a deep curiosity about natural and social interactions and often highlight evolutionary relationships that remind humans of their place in, and responsibility to conserve, nature. Her article "Don't Jump!" published in Slate, won an ASJA award in the op-ed category. She's a visiting scholar at NYU, a 2013 recipient of NYU Reporting Award funding and a Dennis Hunt health journalism fellow. Read her previous contributions to QUEST, a project dedicated to exploring the Science of Sustainability.
  • http://pulse.yahoo.com/_EC7RUZWKCS7F77O2OP7TD566YU heresyourcopy

    The problem with the whole 'cat vs bird' debate is it's an invalid argument. You say that studies show TNR doesn't work but what studies are these? Which feral cat groups were queried for this article? It sounds like you asked some people who manage cat colonies; I'm sure they mean well but that's not science. The other groups mentioned (Audubon, ABC) have a serious anti-cat agenda which means their studies are tainted. That's also not science. As always, the real issue here is "Human vs Bird," for humans are truly the bird's greatest threat. Why do we spend so much time vilifying feral cats when we should be focused on our own actions that destroy the habitats of many wild creatures? Is it because cats can't talk back?

  • pedrolobo

    Lisa, you do your readers a serious disservice by weighing in on this complex, controversial without doing adequate research (alarming, in light of your credentials). A few comments, if I may…

    1. You suggest that “by most accounts, feral cats face a miserable life.” While it’s generally acknowledged that more than half of kittens born “in the wild” don’t survive into adulthood (Levy, Gale, & Gale, 2003), caretakers of sterilized, vaccinated cat colonies often report of cats living long, healthy lives. More than half of the 23 cats living continuously on the University of Central Florida campus during an 11-year observation period, for example, were estimated to be 6.8 years old or older (Levy et al., 2003). A 2012 nationwide survey conducted by Alley Cat Rescue revealed similar longevity: one quarter of TNR organizations responding to the survey have colony cats in the 6–8 year range; 35 percent in the 9–12 year range, and 14 percent reported caring for cats 13 years of age or older (ACR, 2012).

    2. About those “hundreds of millions of native birds, mammals, reptiles, amphibians, and fish” killed every year by cats, might I suggest you consult different “experts”? Such aggregate “estimates” can typically be traced to small (often flawed) studies, the results of which are subsequently extrapolated from one habitat to another, conflating island populations (where the presence of cats can have dire consequences) and those on continents, combining common and rare bird species, and so forth.

    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” (Fitzgerald & Turner, 2000).

    Something else to keep in mind: predators—cats included—tend to prey on the young, the old, the weak and unhealthy. At least two studies have investigated this in great detail, revealing that birds killed by cats are, on average, significantly less healthy that birds killed through non-predatory events (e.g., collisions with windows or cars) and (Møller & Erritzøe, 2000; Baker, Molony, Stone, Cuthill, & Harris, 2008).

    As the UK’s Royal Society for the Protection of Birds notes: “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” (RSPB, 2011).

    3. And, as Animal People’s Merritt Clifton pointed out in a 2003 story, the wildlife rehabilitation perspective simply doesn’t provide one with information sufficient to infer much about population dynamics. The birds brought to the Lindsey Museum “are among the few who are rescued by humans, typically because the humans intervene to break off the cat attack” (Clifton, 2003).

    “That changes the predator/prey dynamic. The cat has no opportunity to finish the kill because of the human intervention. Otherwise, the injuries… would impair flight, and would lead to a cat meal. These are not failures of predation, but successes, interrupted, comparable to what happens when a hyena chases a cheetah off a half-dead gazelle and appropriates the meal for himself.

    The true failures of predation rise into the air and get away unscathed. The… hypothesis that large numbers of birds are dying in the wild of cat-inflicted injuries and infections is simply not supported by evidence,¬¬ whereas roadkilled birds and the remains of birds who collide with windows, transmission towers, and power lines, as well as those who succumb to pesticides, have all been collected and studied by researchers in bucketloads” (Clifton, 2003).

    4. The East Bay parks study you refer is plagued with methodological problems—beginning with the fact that Cole Hawkins, the PhD student undertaking the work, had no idea what the “cat area” was like before the cats arrived. He, therefore, had no way of measuring their impact. Interestingly, Hawkins ignores almost entirely the fact that five of the nine ground-feeding species included in his study showed no preference for either area (Hawkins, 1998). If he can’t explain why these birds were unaffected by the presence of cats nearby, he’s in no position to blame the cats for the absence of the others. Indeed, Hawkins’ scat analysis suggests that predation on birds was minimal: just four percent of 120 scats contained feathers.

    5. Your reference to cats competing for raptors’ prey is, whether you know it or not, a reference to the often-cited—but rarely read—1974 paper by William George. In fact, what George wrote was this:

    “I am not suggesting a cause-and-effect relationship exists between the historical increase of cats and the historical decrease of raptors; however, cats, which are as efficient in their way as guns and DDT, accompany and add another dimension to man’s encroachment into wildlife areas” (George, 1974).

    And, as I discussed in some detail in a November 2010 blog post (voxfelina [dot] com/2010/11/raptor-sheet/), George’s concerns have proved largely unfounded.

    6. You suggest that “studies fail to support [TNR’s] effectiveness.” In fact, several credible studies have documented its potential for decreasing the number of cats in a particular location. In Randolph County, NC, for example, researchers observed a 36 percent average decrease among six sterilized colonies in the first two years; over that same period, three colonies of unsterilized cats experienced an average 47 percent increase (Stoskopf & Nutter, 2004).

    In Rome, Italy, a survey of caretakers (overseeing 103 cat colonies) revealed a 22 percent decrease overall in the number of cats—despite a 21 percent rate of “cat immigration” (as a result of abandoned and stray cats moving into colonies). Although some colonies experienced initial increases, significant reductions were observed over time, from 16 percent on average after three years to 32 percent after six years. And these figures don’t account for an additional observed benefit, one common to managed colonies: “kittens are almost invariably taken and homed by the cat care-takers” (Natoli et al., 2006).

    A TNR program on the campus of the University of Central Florida begun in 1991 led to the adoption of nearly half (47 percent) of the 155 cats living on campus over an 11-year observation period. In 2002, upon completion of a related six-year study, just 23 cats remained on campus (Levy et al., 2003).

    7. The claims that feral cats pose a significant public health record are little more than scaremongering. Take rabies, for example: of the 49 human rabies cases reported in the U.S. since 1995, 10 were the result of dog bites that occurred outside of the U.S.; the remainder were traced either to wildlife or were of unknown origins (CDC, 2012a). Since 1960, only two cases of human rabies have been attributed to cats (CDC, 2012b).

    To put things into context: you’ve got a much better chance of being killed by lightning—not just struck, but killed by lightning. Data collected by the National Oceanic and Atmospheric Administration show that between 1959 and 2011, 3,947 people in the U.S. were killed by lightning (Holle, 2012).

    That’s roughly 75 deaths annually due to lightning strikes. Think about that for a minute: do you know anybody who’s been killed by lightning? Think about that next time TNR opponents start talking about the rabies threat.

    Interestingly, these same people can never explain—indeed, are never asked to by the media—how exactly a ban on TNR, which would mean many more unsterilized and unvaccinated cats, could possibly benefit cats, wildlife, or people. In fact, it’s clear to anybody familiar with the issue that such misguided policy would be detrimental all the way around.

    While I admire your search for “a path to compromise,” I don’t see how we’ll resolve this issue as long as the media does such a poor job reporting the science. I expect more of a writer/editor with your credentials, and I expect more of KQED/NPR.

    Peter J. Wolf
    VoxFelina [dot] com

    Literature Cited
    • ACR. (2012). Alley Cat Rescue's National Feral Cat Survey [Electronic Version]. PR Newswire.
    • Baker, P. J., Molony, S. E., Stone, E., Cuthill, I. C., & Harris, S. (2008). Cats about town: Is predation by free-ranging pet cats Felis catus likely to affect urban bird populations? Ibis, 150, 86–99.
    • CDC. (2012a). Human Rabies. Atlanta (GA): Centers for Disease Control and Prevention
    • CDC. (2012b). Recovery of a Patient from Clinical Rabies—California, 2011. Morbidity and Mortality Weekly Report, 61(4), 61–64.
    • Clifton, M. (2003, June). Where cats belong—and where they don’t. Animal People.
    • Fitzgerald, B. M., & Turner, D. C. (2000). Hunting Behaviour of domestic cats and their impact on prey populations. In D. C. Turner & P. P. G. Bateson (Eds.), The Domestic Cat: The biology of its behaviour (2nd ed., pp. 151–175). Cambridge, U.K.; New York: Cambridge University Press.
    • George, W. (1974). Domestic cats as predators and factors in winter shortages of raptor prey. The Wilson Bulletin, 86(4), 384–396.
    • Hawkins, C. C. (1998). Impact of a subsidized exotic predator on native biota: Effect of house cats (Felis catus) on California birds and rodents. Unpublished PhD Dissertation, Texas A&M University.
    • Holle, R. (2012). Lightning Fatalities by State, 1959–2011. Tucson, AZ: Vaisala.
    • Levy, J. K., Gale, D. W., & Gale, L. A. (2003). 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, 222(1), 42-46.
    • Møller, A. P., & Erritzøe, J. (2000). Predation against birds with low immunocompetence. Oecologia, 122(4), 500–504.
    • Natoli, E., Maragliano, L., Cariola, G., Faini, A., Bonanni, R., Cafazzo, S., et al. (2006). Management of feral domestic cats in the urban environment of Rome (Italy). Preventive Veterinary Medicine, 77(3-4), 180–185.
    • RSPB. (2011). Are cats causing bird declines? [Electronic Version]. Retrieved October 26, 2011, from rspb [dot] org.uk/advice/gardening/unwantedvisitors/cats/birddeclines.aspx
    • Stoskopf, M. K., & Nutter, F. B. (2004). Analyzing approaches to feral cat management—one size does not fit all. Journal of the American Veterinary Medical Association, 225(9), 1361–1364.

  • Nils

    Lisa, your article was as fair and balanced as it could be. I assure your that if the people who typically debate with the authors who wrote the last two comments find this article they would be taking you to task for being biased towards cats and not researching the science that supports their positions. That reflects on of the findings in our paper: values more than science will determine how people respond to the issue.