Having only read the first page of responses to this post: I can say by experience: "house" cats, kill more animals than just birds. House cats (aka pets) and "house" cats whom have been abandoned in rural areas, (aka feral cats), kill baby wild rabbits, and others such animals.
Not just "song" birds, but also "feral cats and pet cats" kill baby/young turkeys, baby/young squirrels, and of course receive the congratulations for killing mice, rats, and other such nuisance critters that invade homes.
Then there are the "pet" vs "feral" cat fights over cat food by cat owners feeding their pets outside vs inside the home. (Personal experience, feeding neighbor's cat and dogs).
Unlike some who will post to say nothing and go about your business quietly, I say try to educate the closed minded antis and those who are skeptical - neither pro nor anti, pervebial fence sitters, to the problem that plagues wildlife: feral pets- cats and dogs.
Just my 2 cents on this topic.