Well, it is obvious your cat had nothing to do with it. And all creatures die of something, eventually, even though it is so sad when they do. One thing I miss out on here, by having Retrievers and indoor/outdoor cats is feeding the wild birds. I have feeders, bluebird houses and bird baths that I simply cannot bring myself to use because I know I would be asking for trouble. Honey (the Golden Retriever) has been known to catch a bird in flight in the backyard. She doesn't kill them intentionally, but using her Retriever skills, she "mouths" them, and using her "keep away" skills, she won't let me get close enough to her to take them away. Thank goodness it has been over a year since the last time I witnessed her doing this.