I have to resurrect this thread because it has happened. I now have a woodpecker going after my entirely wood barn.
My husband heard him, but as he got closer it flew away. We just went out to check where he thought the damn thing was, and I noticed two brand new medium sized holes in a panel of wood. The thing is that it pecked in the piece of wood where there was one carpenter bee hole through which I was unable to evict the tenants (it's up high in the rafters, a single hole, so after evicting bees from 50+ other easily-reached holes I kind of said "screw it" and left it). So far, that is the only damage I see.
This barn is at least 20 years old and I do not see any other damage, old or new, from woodpeckers. We also have left two giant old dying trees right next to the barn for the sole purpose of providing a pecking place/home for these bastards.
What should I do? Ridding my barn of wood is impossible without tearing the entire thing down. I plan to try pre-emptive measures around the immediate area where he pecked (reflective tape worked well for my friend for whom I started this thread originally), but I am hoping that he just found the one spot where I didn't get rid of the carpenter bees and took it upon himself to do the job. Is that a silly notion? Am I being too hopeful?