Your house cat(s) probably don't do much damage. Something like 2/3rds of domesticated cats are feral. All told, cats kill > 1 billions birds in North America

Your house cat(s) probably don't do much damage. Something like 2/3rds of domesticated cats are feral. All told, cats kill > 1 billions birds in North America. Like this article says, with so many factors and poor data collection, it's hard to quantify everything. But please do your part. If your cat does go outside, please consider putting a bell on their collar.