Cats on the Prowl
still locate prey with their sense of touch. Special nerve endings at the base of their whiskers allow cats to feel slight changes in air currents caused by a mouse walking back to its nest or a thrush stirring silently in a bush at night.
It's easy to tell when a cat is ready to spring into action. For instance, when it spots a junco feeding on the ground near a feeder, it flicks its tail, flattens its ears and quietly moves forward. When in range, it stops, curls its back, then leaps next to the bird. The back paws touch the ground beside the junco, so the cat can quickly sink its teeth and claws into the bird.
Many cat owners do not witness this deadly ballet. Instead, they see only about half the birds that cats kill, according to several studies. To discover the effects of house cats on birds and other small mammals, Peter B. Churcher and John H. Lawton studied 78 cats that lived in a small Bedfordshire village in England.
For a year, all the cat owners but one collected the remains of animals their cats had killed. When possible, they also noted catches they witnessed where no remains were left. The researchers discovered that 35 percent of the annual total was birds. The percentage rose during the winter when small mammals weren't as active.
Sixteen percent of all kills were house sparrows. By studying the number of sparrows in the area and comparing it to the number the cats brought home, the researchers concluded that between a third and a half of all sparrow deaths were caused by cats. They also discovered that cats that lived in the interior of the village killed more birds than those that lived near fields.
In conclusion, Churcher and Lawton then multiplied the mean annual catch of the village cats by the estimated total of domestic cats in Britain. The result was 70 million kills, of which between 30 to 50 percent may be birds. They concluded that cats in England kill at least 20 million birds each year.
In the United States, Craven, Coleman and Temple estimate that rural cats alone kill more than a billion small mammals and hundreds of millions of birds each year. Urban and suburban cats--especially if they have limited access to rodents--cause the estimate to go higher.
Cats, of course, aren't the only threat to birds. Combine the cat's