Now that I think about it, I was talking to a tree removal expert (urban
logger). He said that woodpeckers just love dead trees. He often leaves a
trunk and a couple branches jusr for the woodpeckers. He has even brought a
dead tree to another location and mounted it on a solid platform, just for
the birds. I don't know if they will leave your garage for a dead tree
though. But it is an interesting idea.