To get rid of mice outside my home (hopefully before any of them find a way into my house) I've used plastic rat traps baited with peanut butter. For the past few years these traps have worked well, and it was not unusual for me to find 3 or 4 trapped and dead mice daily in the 8 to 10 traps that I put out. But this year is different. While I am still catching some, I daily find some of my traps sprunIg or unsprung with the bait gone. I guess its possible that some other critters are getting the bait without tripping the trap, but I suspect that it is mice. It appears as if the mice around here have learned how to gently nibble the bait without setting the trap off, and maybe are teaching other mice how to do as well.