A new relationship with animals, nature and each other.

On Wildlife Murder, the Cat’s Out of the Bag


A new study makes the powerful case that cats who are left to roam out of doors are doing enormous damage to wildlife. Cat lovers and cat protection groups can howl and claw back as much as they like, but the fact is we’ve all known for a long time that felis silvestris catus is a natural born killer.

While many cat protection groups say that far more birds are killed by flying into high-rise buildings, windmills, etc., these arguments have become a bit like Ronald Reagan preferring to believe that he didn’t sell arms to the contras in Nicaragua. (“in my heart, I still believe that we did not sell arms for hostages, but the evidence appears to indicate otherwise.”) In the case of cats and their prey, the evidence now appears to be overwhelming:

We estimate that free-ranging domestic cats kill 1.4–3.7 billion birds and 6.9–20.7 billion mammals annually. Un-owned cats, as opposed to owned pets, cause the majority of this mortality. Our findings suggest that free-ranging cats cause substantially greater wildlife mortality than previously thought and are likely the single greatest source of anthropogenic mortality for US birds and mammals.

It doesn’t help that cat welfare groups are often at war with bird welfare groups. While we don’t know exactly how many birds live in or migrate through the United States each year, the enormous numbers of birds killed by cats may amount to 15 percent of the entire avian population, according to Pete Marra, an animal ecologist with the Smithsonian Conservation Biology Institute and co-author of the study.

The enormous numbers of birds killed by cats may amount to 15 percent of the entire avian population.

“A lot of these cats may go outside and go to 10 different houses, but they go back to their house and cuddle up on Mr. Smith’s lap at night,” Marra said. And the study estimated that each of those kitties kills up to 18 birds and 21 small mammals a year.

One argument put forward by cat people at home is that it’s not their well-fed pets who are causing the damage but rather feral cats. Household pets, they say, have no need to kill small animals. This, however, is untrue: Household cats don’t kill because they’re starving; they kill because that’s what they do.

Conversely, feral cat groups argue that ferals don’t have the energy for recreational killing. This is also a fantasy. The new study indicates that feral cats are by far the bigger problem. The authors estimate that at any given time there are between 30 million and 80 million ferals in the United States, and that on average each of them kills between 23 and 46 birds a year, and between 129 and 338 small mammals.

Why would we be surprised by any of this? Wasn’t it their hunting ability that led cats to become our best friends in the first place?

bastet-013013In Ancient Egypt, the domestication process began when humans fell in love with the fact that cats were protecting their grain stores from mice. Humans loved grain and cats loved mice. What better partnership could there be? Cats were promptly elevated to the status of goddesses, and for hundreds of years the Great Cat Goddess Bastet ruled supreme. At times, it was even a capital offence to kill a cat, even by accident.

In our own time, most of us who have ever let Fluffy outside have seen her return with little “gifts”. (Yes, we like to think of her killer intentions as an act of loving kindness.) So we should hardly be surprised to know that when she’s not gaining fame as a great pianist, Fluffy is out there watching for anything small that moves.

At around the same time that the new study was released, a prominent economist in New Zealand was pushing for draconian new measures to reduce the destruction of native wildlife by cats in his own country.

Gareth Morgan, who is also an environmentalist, calls cats “friendly neighborhood serial killers” when it comes to birds, and points to a study showing that they are already responsible for the extinction of nine native bird species. Another 33 bird species are now endangered. Morgan is pushing for draconian new measures to reduce the destruction of native wildlife by cats in New Zealand.

Morgan wants New Zealanders to gradually reduce the local feline population by having all cats neutered, and, when their pet cats die, to not replace them.

He also wants feral cats to be killed. But it’s long been the experience of people working to reduce feral cat populations that killing cats does not reduce the problem since the remaining cats just breed more, and other feral cats move in from neighboring areas. The answer, they argue, is trap/neuter/return (TNR) programs that gradually reduce the numbers – in many cases to zero.

That’s true where it’s true. But Australia is a good example of a region where the arrival of cats on ships from Europe introduced an invasive species for which the native animals had no defenses. As a result, feral cats by the millions are now at large in wild areas (“the bush”) and neither TNR nor figuring out ways of killing the cats is going to make a dent in what’s happening.

The same is the case in New Zealand. And when Bob Kerridge, executive director of the Auckland SPCA, told the New York Times that we should “leave it to nature to take care of things,” he was talking utter nonsense. When invasive species take over, this is hardly nature “taking care of things.”

Of course, the truly problematic invasive species is not the cats. They, too, like the native wildlife, are simply the innocent victims of another species, humans, that has invaded every corner of the Earth, bringing danger, disease and destruction along for the ride.


Currently, in Florida, we have another wildlife catastrophe on our hands. Tens of thousands of Burmese pythons (some say up to 180,000) are loose in the Everglades as a result of criminally irresponsible “pet owners” and former breeders dumping their unwanted “pets” out in the wild. Pythons grow very large – up to 17 feet long – and can swallow a deer for dinner. A female python can have up to a hundred eggs. Entire populations of rabbits and foxes have disappeared from the Everglades, and populations of raccoons, opossums and bobcats have dropped as much as 99 percent.

Entire populations of rabbits and foxes have disappeared from the Everglades, and raccoons, opossums and bobcats have dropped as much as 99 percent.

Earlier this month, the Florida Fish and Wildlife Conservation Commission launched a hunting competition with prizes to people who can kill the most pythons.

But more killing is rarely, if ever, the solution to anything. And, frankly, we just don’t have a good answer. If we don’t kill the pythons, we’re responsible for all the killing they do. If we do kill them, we’re just killing more innocent creatures ourselves.

The same goes for the cats in New Zealand and Australia.

But it’s not yet the same for the cats in the United States. Rather than tilting at windmills and skyscrapers, the animal protection world can take action to press in all directions for household cats to be contained indoors or in outdoor catteries or on leashes. That will resolve a large measure of the problem. And trap/neuter/return programs need to become embedded in city and county ordinances and in the culture of every neighborhood.

Of course, that’s what cat protection groups have been saying all along, and it’s still only slowly catching on. But at least, unlike with the pythons in the Everglades and the cats Downunder, we know what the answer is for the cats who are killing wildlife here in the U.S.

So, if we don’t do what we know is right, it’s not the cats who are the killers; it’s us.