Laura Erickson's For the Birds

Now that I’m on the Internet and subscribe to the National Bird Chat, I’m able to keep up with bird information from all over—I get inundated with too much to keep up with everything. Some of it is worthless—I really don’t need to know about the personal bedroom and bathroom lists that some subscribers announce to the world, for example, but some information I get is so valuable and timely that I wonder how I could even produce this program before I got on line. Last week, for example, I learned of a web site with a brochure filled with information about the effects of house cats on birds, including an excellent bibliography, produced by John Coleman, Stan Temple, and Scott Craven of the University of Wisconsin.

This brochure is not copyrighted—as a matter of fact, the authors specifically permit and even encourage duplication, hoping to get the information out to as many people as possible.

Cats were first domesticated in Egypt around 2000 BC, but didn’t catch on anywhere else for a long time, perhaps in part because Egyptians didn’t allow the export of creatures worshipped as goddesses. But around 500 BC the cat got out of the bag, so to speak, when the Greeks discovered and shared them with the world. Now the authors estimate that there are 100 million domestic cats in the United States, including pets, semi-wild, and free-ranging cats.

Cats are obviously natural predators, and so some people believe that they fit in with nature. But the problem is, subsidized cats have far more than natural effects on their prey. First, unlike natural predators, pet cats are protected from disease, predation, and the effects of competition, so there are few natural checks on their numbers. Second, they often have a dependable supply of supplemental food provided by their owners, and so their numbers don’t decrease as their prey does. And third, their densities aren’t limited by territoriality—unlike foxes or other natural predators, there can be a dozen cats on a single suburban block. Based on a large number of studies, the authors estimate that in Wisconsin alone, cats kill about 39 million birds every year.

According to this brochure, worldwide, cats may have been involved in the extinction of more bird species than any other cause except habitat destruction. In the US, they are contributing to the endangerment of species such as Least Terns, Piping Plovers, and Loggerhead Shrikes.

So what do we do about cats? Spaying or neutering pets helps keep the cat population down, and, just as critically, people should keep their cats indoors. I know this seems heartless when a kitty is pleading to be let out, but the suffering and death they inflict on birds more than offsets that, and even the most outdoor cat really can eventually adapt to being stuck indoors. A dividend of keeping cats indoors is that they will live longer, safer lives.

If you want a copy of this brochure, titled Cats and Wildlife, a Conservation Dilemma, you can get it through my homepage, or by writing to “For the Birds” in care of this station.