One must never use poisoned bait. The mice ingest it Owls eat the mice and die. They are the raptors that keep the mice population down so that is awful. I use live traps filled with peanut butter. I then take the mice out to an open field away from housing and release. It works good. Also have a cat whose function is to catch any mouse that gets into the house. He is a house cat because we have resident coyotes. So, he is only allowed indoor pests.