Old Barney likes to pound holes in trees. It's some serious pounding. If he doesn't use the holes himself, various other birds like swifts, owls, ducks, bats and martens, are happy to take up residence. In fact, a lot of times you can see these other birds taunting Barney so he follows them around from tree to tree banging holes for them. I'm not sure old Barney is too bright!