@Sheril Humans have removed most predators from our landscapes allowing small birds to flourish in a way they would not naturally be able. Despite the cat predation, we don't see any small birds in danger of extinction.

Cats pose no danger for condors, and condors are unlikely to be flying into glass buildings. So we would want to know what kind of birds are flying into the wind turbines. If condors ... that's a problem. If seagulls ... not so much.