Feral Cats, or How I Learned to Stop Worrying and Love the Cull


The United States is facing a crisis of feral cats. It’s time to talk brass tacks about solving the problem, for the sake of our native wildlife. Source: Marine Corps Base Hawaii


“But why can’t he be an outdoor cat? Maine coons are meant to be out in nature,” my brother said, eyeing Elijah, our then-new cat who has since grown to a size double that of a normal house cat.

“Because,” I said, incredulously, “just look at him! If he gets outside, he’ll eat every single bird from our backyard. It’d be a disaster.” 

In that moment, I recalled the grisly sight of a feral cat with a dead Yellow Warbler in its mouth during one of my regular bird walks at Vassar Farm. I thought how that warbler, who had flown thousands of miles from his wintering grounds in Central America to breed at the farm, had had his bright life snuffed out by a hungry feral cat.

I also wondered how many people would shrug at the death of the warbler because of our tenacious cultural attachment to cats. 

Elijah is now three years old and enjoys his life as an indoor cat, hunting squeaky toys rather than wild critters. If we’d allowed him to grow up into an outdoor cat, he’d be no different than any of our country’s enormous population of feral cats—a death knell for many common and threatened native species of wildlife in the U.S.

Yellow Warblers like this one are a common migratory songbird in the U.S. Like many warblers, sparrows, and other small bird species, cats are a huge threat to these beautiful songsters. © David Chernack

Exact estimates vary, but various sources report that there are between 50 and 70 million feral cats in the United States. Some reports point to figures above 100 million. That’s a lot of cats, considering American pet owners only registered 94.2 million pet cats in 2017.

But why are these cats so acutely problematic? 

A 2012 study estimated that a single feral cat kills 23 to 46 birds per year—25% of which they don’t eat—and an outdoor pet cat can match those figures. This means that the U.S. feral and outdoor cat populations combined can rack up 1.4 billion to 3.7 billion bird kills per year. That’s a far higher toll than the still-significant 600 million birds killed in window collisions and up to 340 million killed in vehicle collisions every year. 

The total across all species of wildlife is even more grave: when reptiles, amphibians, and small mammals are included in the tally, scientists estimate that feral cats in the U.S. kill 6.9 to 20.7 billion animals annually. Outside of human-driven habitat destruction, there is arguably no greater threat to small wildlife species—especially birds—than feral cats. 

So what’s the solution to this big problem? Well, that depends on who you ask. 

Many scientists in government agencies and private research institutions argue for a cull: a coordinated effort to trap and euthanize as many feral cats as possible. To any cat owner, however, that plan is a hard sell. After all, it’s not the cats’ fault that they have become so ecologically problematic—that’s on us, the humans who since 1492 have let cats loose on the Americas and done little to hinder their spread. 

A feral cat colony. Source: United Press International

Until early civilizations domesticated wild cats around 10,000 years ago, small felines (like lynx or ocelots) existed in very low numbers in their natural environs. Until 500 years ago, native wildlife in the Americas didn’t have to contend with the immense predatory pressure of Felis domesticus. Now they do. 

Vocal feral cat advocacy groups, however, reject the very notion of culling efforts. They argue that feral cats are simply living an unproblematic “natural lifestyle.” And while some dispute any deleterious effects of cats on native wildlife, they generally agree that an enormous population of feral felines isn’t great. Their solution? A straightforward strategy of “trap, neuter, and return,” or “TNR.” 

The TNR model is just that: trap feral cats, neuter or spay them, and return them to the environment. A feral cat can have up to three litters or a dozen kittens per year, so spaying a single female can have a big impact on reducing cat numbers. This strategy sounds like a viable, humane solution—until you think about the downsides.

First, feral cats can live for up to a decade, meaning that even after an individual is neutered or spayed, a cat will still kill wildlife for the rest of its life. Second, the strategy is expensive and time-consuming, necessitating extensive training, as well as the involvement of licensed veterinarians. The companion strategy to TNR, mass adoption, is not always possible with wild-reared cats who have no history of human socialization. 

No one wants to kill animals—especially intelligent, culturally important ones like cats—when it’s not necessary. But with feral populations on the rise, we might not have much choice aside from culling.

Some countries have already moved to make that tough choice. Australia implemented a highly-controversial cat cull program in 1999 which has met with some success: since 2015, it’s removed more than 200,000 cats per year from the Australian outback, a region which has been ravaged by feral cats as well as a plague of rabbits for decades. A large proportion of those cats were shot by private landowners and hunters, decreasing the costliness of the program to Australia’s environmental agencies. The Aussie government’s key messaging tactic has been to call feral cats what they are—an invasive species—and that’s worked pretty well so far.

Birds that forage and nest on the ground, like this Ovenbird, are particularly vulnerable to predation by feral cats. © David Chernack

Aside from the expected criticism from groups like PETA, there has also been some scientific criticism of Australia’s cull. As some ecologists accurately point out, feral cats quickly recolonize areas after culls are conducted; thus, continuous monitoring is required. Additionally, they note that the scattershot scope of Australia’s culling strategy has ignored the fact that some endangered species—like the Eastern Bristlebird—should be prioritized when choosing areas in which to conduct culling activities. Instead of encouraging a diffuse national program, resources should be focused on areas where the cats’ impact is most pronounced.

If the U.S. is to adopt such a strategy from the Australians, it must learn the right lessons: educate and involve the public, and keep endangered species in mind. Where culling is not possible, supplementing TNR is certainly a better solution than no intervention at all. 

Culling programs are slow to make their way into official policies in the U.S., and like many causes on municipal dockets, the issue is unlikely to gain any attention or traction during the global COVID-19 pandemic.

In the meantime, the best thing you can do—aside from keeping your kitty indoors—is to have the tough conversation about culling. Confront popular notions about cats’ role in our ecosystems, as I did with our cat Elijah. Feral cats may not be far removed from our indoor housecats, but they are a different animal altogether when it comes to the threat they pose to our native wildlife. 

About davidchernack

Bard CEP M.S. in Environmental Policy Candidate, 2021. Interested in transboundary wildlife conservation, electric vehicles, and ecotourism. Never not birdwatching.