MICHELE NORRIS, host:
From NPR News, this is ALL THINGS CONSIDERED. I'm Michele Norris.
It's possible that the number one killer of American birds is a much beloved pet that sounds like this.
(Soundbite of cats purring)
NORRIS: Experts say domestic cats may kill hundreds of millions of wild birds each year in the United States alone. But nobody is sure, so a conservation group is asking pet owners to help count the dead.
NPR's John Nielsen has more.
JOHN NIELSEN: Household cats turn into expert hunters when they get outside. For example, take Mom Cat(ph), who belonged to Deb Deery(ph) of South Bend, Indiana. Mom Cat was very good at killing mice and birds.
Ms. DEB DEERY: And sometimes she would arrange the body parts, so you'd have a mouse with a bird head on it at one doorstep, and a bird with a mouse head on it on the other doorstep. We thought she was rather odd, but she was our cat and we loved her.
NIELSEN: I met Deery in the park in downtown Washington D.C. where she was more than happy to brag about Mom Cat's hunting skills. Unfortunately, cats like Mom Cat aren't very popular with the people who are trying to save wild birds, like Stanley Temple, a cat predation expert at the University of Wisconsin. He says there are more than a hundred million cats that spend part or all of their life outside living in the United States today. These cats pose a major threat to wild birds like wrens and warblers.
Last year, in an effort to protect these birds, Temple pushed an unsuccessful plan to allow Wisconsin hunters to kill some homeless cats. Instead, many cat lovers came after him.
Mr. STANLEY TEMPLE (Cat Predation Expert, University of Wisconsin): It was one of the most troubling years of my life. I got multiple death threats. You want to listen to one. Try this.
Unidentified Woman: You cat murdering bastard. What goes around comes around. I declare Stanley Temple season open.
NIELSEN: Temple says the woman who left that message on his answering machine is now a convicted felon. More composed opponents of the hunting plan argued that there wasn't enough scientific evidence that cats were doing major harm to birds. And to some extent, they have a valid point, says ornithologist Mike Parr of the American Bird Conservancy.
So far, there are only local studies of the cat predation problem, according to Parr, and estimates of the number of animals killed by the average cat each year range widely.
Mr. MIKE PARR (Vice President, American Bird Conservancy): From just a few birds or mammals being killed by each cats, up to - in one study there was one cat that killed over a thousand small animals.
NIELSEN: To fill in some of those data gaps, the American Bird Conservancy is now asking the public to help them keep track of all the animals pets leave in front hallways around the country. The conservancy has created a Web site called Project Predator Watch, and Parr says the basic principle is simple. When you see a cat or a dog kill a bird, a squirrel or anything else, you go to the Predator Watch Web page and share the gory details.
Mr. PARR: What we'd like to find out is exactly what's going on not only in our backyards but across the broader landscape and, ultimately, what can we do about it.
NIELSEN: All kinds of minor details could turn out to be important, says conservancy spokesman Gavin Shire, like whether a cat is wearing a bell, or whether it's been de-clawed, or whether it's got brightly colored fur.
Mr. GAVIN SHIRE (Spokesman, American Bird Conservancy): It's quite possible that we'll find out that brightly colored cats are less successful in catching birds than more critically colored cats. You'll never know what you're going to find until you analyze the results.
NIELSEN: It's possible that this survey will turn up some good news, for cat owners in particular. For instance, it might show that cats eat lots of rats, which in turn eat lots of bird eggs.
Whether pet owners will take the time to fill out all these questionnaires remains an open question. But at least one cat owner says she thinks it's worth the effort. That's Deb Deery from South Bend, Indiana, who says Mom Cat wasn't the only bird killer in her neighborhood.
Ms. DEERY: We had what we call the crazy cat lady. And while she was alive, there were very few wild birds in the neighborhood. We had no cardinals. We had no big birds. The cats just got them. And once she was gone and the cats were gone, all the birds came back.
NIELSEN: Deery adds that her cats won't be killing any more birds because she doesn't have any more cats. Mom Cat died a while ago and now her children are allergic.
John Nielsen, NPR News, Washington.