Housecats Kill Hundreds of Millions of Birds Annually

Housecat with Yellow-rumped Warbler, photo courtesy of American Bird Conservancy

Here in the South our local birds are well into their nesting season. Around the yard I've seen active nests of robins, cardinals, and Carolina wrens in the trees and shrubs. Won't be long before their young are fledging and at their most vulnerable stage.

The migratory warblers that nest farther north are coming through our area too, from their wintering grounds in Latin America. We can hear their calls in the trees behind the house.

The chipmunks are up and about too. The entries to their nest holes are tidied, and I see the mamas darting around the yard looking for anything edible. The little nurslings are underground now, but they'll be up above ground soon. Last year I saw a mom with three babies, all sitting straight up like little meerkats.

I love this time of year. But I hate it too - because I know before long I'll see my neighbors' cats carrying songbirds and struggling chipmunks out of my yard. If this year is like last year, I'll see the cats hunting in my yard every single day.

Scientists estimate that housecats in the U.S. alone kill close to a billion birds every year. They also kill around a billion small mammals annually. (See links to publications below.)

There is nothing "natural" about housecats preying on native wildlife. Cats are an introduced species, and like kudzu or honeysuckle, they are not affected by the natural checks that limit the numbers of native species. Housecats are kept in prime hunting condition by the feeding and medical care they receive from us. They are far more efficient hunters and are far more numerous than any naturally occurring predator ever was. Unfortunately, bird populations are already suffering from habitat loss and other human impacts. House cats are one additional blow - one that we could control easily.

If you have a cat, you might want to know that hanging a bell on the cat does not work, nor does declawing. The only thing that stops cats from killing native wildlife is keeping them indoors.

If you have a cat, you might also like to know that your cat's life expectancy will be much higher if you keep it indoors. Roaming cats can expect to live an average of less than 3 years, while indoor cats can expect to live 15-18 years.

I did, a couple of years ago, go talk to my neighbors about their cats. I begged them to keep the cats indoors. I gave them reprints of all the articles cited here. But they said the kitties would be unhappy indoors, so the kitties still roam.

Here are some great articles from the Humane Society, the American Bird Conservancy, and other respected sources about the merits of keeping cats indoors:

HSUS, the Humane Society, has a great paper about the benefits to cats of living indoors, including the improved life expectancy. Indoor cats are safe from cars and other accidents, and have fewer illnesses.

The American Bird Conservancy has some great articles and fact sheets about the impact of housecats on wildlife, including materials for educators. One of their interesting fact sheets is "Human Attitudes and Behaviors Regarding Cats", which says:

35% of cat owners keep their cats indoors all the time
53% of cat owners are concerned about cat predation
64% of survey respondents believe putting bells on cats keeps them from killing (untrue)
70% of respondents believe cats should be regulated to prevent roaming

A 2006 paper by ecologists in Wisconsin lists a number a resources and other papers that will be useful to anyone researching this topic.

This University of Maine paper says that there were around 30 million cats in the U.S. in 1970. The paper estimates that there are now around 100 million in the U.S.

I would love to hear from readers any other stories of neighborhood cats on the prowl, with good endings or bad.

Keywords: house cats housecats domestic cats feral cats predation birds small mammals invasive species