You all may be surprised to hear this, but my varmint exterminator of choice is a .177 spring pellet rifle. Of course, if I didn't live in a densely populated area I'd probably choose something else out of my collection, but it has stopped everything with no collateral damage. Chipmunk, squirrel, rabbit, possum, skunk, woodchuck, raccoon have all taken a single pellet to the head. The raccoon took two because his head was in the tree so I had to zing his butt first to get him to turn around. Nice thing is no evidence and not enough noise to attract attention.
It's also extremely good for euthanizing injured birds.