 The domestic cat is a significant predator of birds . UK assessments indicate they may be accountable for an estimated 64 @.@ 8 million bird deaths each year . Certain species appear more susceptible than others ; for example , 30 % of house sparrow mortality is linked to the domestic cat . In the recovery of ringed robins ( Erithacus rubecula ) and <unk> ( Prunella <unk> ) , 31 % of deaths were a result of cat predation . The presence of larger carnivores such as coyotes which prey on cats and other small predators reduces the effect of predation by cats and other small predators such as opossums and raccoons on bird numbers and variety . The proposal that cat populations will increase when the numbers of these top predators decline is called the <unk> release hypothesis . However , a new study suggests cats are a much greater menace than previously thought and feral cats kill several billion birds each year in the United States . 
