According to the Alberta Institute for Wildlife Conservation (AIWC), American Robins are 10% of all of the birds admitted for rehabiliation during the summer. 31% are brought in after being caught by a domestic cat. To treat a bird after it has been bitten by a cat can require antibiotics for up to 14 days, due to the bacteria that is transferred in cat saliva. The cost can be $100 or more for each bird.

A study of 41 free-roaming cats in Kansas showed that 83% killed wild birds, including de-clawed cats.

There are over 77 million pet cats in the United States alone, and about 35% are kept indoors. This leaves millions of cats outdoors and does not include the many stray and feral cats. Scientists estimate that cats kill hundreds of millions of birds, making them the second greatest threat to wild birds around the world.