I have a life-sized headless horseman on a horse that I carved out of styrofoam as part of my big Halloween yard display. The other day I noticed a bird on the horse's neck and upon further investigation I saw it was a woodpecker! I checked under the horse's chin and sure enough there is a tunnel bored there in the styrofoam and the woodpecker is living inside! When the spotlights came on at night he poked his head out of the hole to see what was going on, so I took his picture (see below). I'm not going to plug up the hole because he'll probably just make a new one!