A new relationship with animals, nature and each other.

Are Cats Wiping Out Birds?

It’s been something of a feud between cat people and bird people: the question of how much damage our cats are doing to the bird population.

The American Bird Conservancy has long argued that cats – feral cats in particular – are wiping out whole populations of birds. Cat people have fought back, saying that feral cats rarely have birds on their menu, that killing off the cats doesn’t work, and that any damage to birds is being done largely by pet cats.

Of course, it shouldn’t have become an either/or proposition. But things have a way of going that way.

New studies are giving strong evidence of just how many birds are being killed by cats – both pet and feral. In the United States alone, according to a new study, 500 million birds fall prey to cats every year, along with three billion other small animals.

One of the studies, from the University of Georgia and National Geographic, was of the behavior of pet cats who had access to the outdoors. Small cameras were attached to special collars on 60 outdoor housecats in Athens, Georgia. The cats spent about six hours outdoors each day.

“The results were certainly surprising, if not startling,” said Kerrie Anne Loyd of the University of Georgia, who was the lead author of the study. “In Athens-Clarke County, we found that about 30 percent of the sampled cats were successful in capturing and killing prey, and that those cats averaged about one kill for every 17 hours outdoors or 2.1 kills per week. It was also surprising to learn that cats only brought 23 percent of their kills back to a residence. We found that house cats will kill a wide variety of animals, including: lizards, voles, chipmunks, birds, frogs, and small snakes.”

This kitty was following a chipmunk:


And this one was following an opossum: (See more photos and video at the U. of Georgia kittycam page.)


The cats brought home just one in four of the animals they killed, ate one in three, and left half of them to rot.

The cats weren’t only a danger to these other animals; they were endangering themselves, too. They were seen crossing roads (45%), eating and drinking things they found (25%), exploring storm drains (20%) and entering crawl spaces where they could become trapped (20%). Male cats were more likely to do risky things than female cats, and older cats were more careful than younger ones.

Another study conducted in Illinois showed just how far a roaming cat can go, finding that housecats had a range of up to 370 acres, and feral cats  up to 1,351 acres!

Wildlife advocates like the American Bird Conservancy (ABC) say with a population of 74 million housecats in the United States, this adds up to a huge level of carnage. “Cat predation is one of the reasons why one in three American birds species are in decline,” said George Fenwick, president of ABC.

“I think it will be impossible to deny the ongoing slaughter of wildlife by outdoor cats given the videotape documentation and the scientific credibility that this study brings,” said Michael Hutchins, Executive Director of The Wildlife Society, the leading organization for wildlife professionals in the United States. “There is a huge environmental price that we are paying every single day that we turn our backs on our native wildlife in favor of protecting non-native predatory cats at all cost while ignoring the inconvenient truth about the mortality they inflict.” “It will be impossible to deny the ongoing slaughter of wildlife by outdoor cats given the videotape documentation and the scientific credibility that this study brings.”

The University of Nebraska study, released last year, found that feral cats were responsible for the extinction of 33 species of birds worldwide, that even well fed cats in managed cat colonies do hunt and kill other animals, and that feral cats prey more on native wildlife than on invasive species. (For the record, both cats and humans could be classified as invasive species.)

Animal protection groups that advocate trap-neuter-return (TNR) programs for feral cats argue that killing the cats accomplishes nothing. The “vacuum effect” shows that feral cats regulate their breeding to fill the available space. Kill some here, and more will move in from over there. TNR, they say, is not only the more humane approach to feral cats; it’s also the most practical way of gradually reducing the population.

And, of course, the species that’s taking by far the biggest toll on wildlife is humans. A 2000 report by the World Conservation Union surveying 1,173 threatened bird species, showed that habitat loss was the most important threat, affecting 83% of the bird species sampled. According to the World Watch Institute:

“…[P]eople have always modified natural landscapes in the course of finding food, obtaining shelter, and meeting other requirements of daily life. What makes present-day human alteration of habitat the number-one problem for birds and other creatures is its unprecedented scale and intensity.

Alley Cat Allies reports that nearly 100 million birds die each year from colliding with windows, 80 million from collisions with automobiles, and about 70 million from exposure to pesticides.

There’s no simple overall solution. The cat, so to speak, is out of the back. And killing more kitties isn’t going to save more birds.

Progress is being made by TNR groups, and anyone can participate in a local TNR program.

And the one thing we can all do is keep our cats in a protected area with an outdoor cattery or cat-proof fenced area (numerous products are available online) where they can enjoy the outdoors and let other animals do the same.