Cats and Bird Kills

Most cat owners have seen cats play with mice before killing them. The cat tosses the mouse in the air, bats it, rolls it over, clasps it, and kicks at it using its hind claws. The reasons cats play with their prey is not clear. Leyhausen favored the explanation that this play represents the release of pent-up energy associated with predatory behavior and is not necessarily done for pleasure.

A disturbing picture of feline backyard predatory behavior emerged in a 1989 study by biologist Peter Churcher of Bedford School in Bedfordshire, England, and ecologist John Lawton of the University of London. These investigators recorded the number and kind of prey brought home by 77 normal pet cats living in a village in Bedfordshire. They found that in a year's time almost 1,100 prey were claimed by the cats. About 64 per cent of the kill were small mammals, and 36 per cent were birds, including song thrushes, blackbirds, and robins. When they used these figures to calculate the impact of the entire population of 5 million house cats throughout Great Britain, they estimated the pet cats kill at least 20 million birds a year.

The larger number of cats in the United States probably prey on rodents and birds in much greater numbers. In fact, ecologists say that the British study no doubt underestimated the number of birds cats kill, because house cats bring home only about half their victims. In January 1992, California scientists said that cats have all but eliminated the wild bird population in San Francisco's Golden Gate Park.