how are you going to be like "my anecdote is actually important" with an N of magnitude 100. long-term and wide-scale research and monitoring has tracked millions of birds and have used models to extrapolate to the billions. your comment means little more than nothing. have you considered you haven't seen the extent of what the roaming cat has killed? it won't always bring it back to you. and why is it that the non-bird animals aren't important? biodiversity reduction, not just birds. and you think that even if they are sick or injured catches that your cat isn't impacting the other animals? you realize other animals gotta eat? if they can't b/c your cat takes it, or worst infects it with a parasite by chomping on it, your local predators are gonna suffer.