@Tai Chi,
I worked at a seasonal craft school that had 20 cabins with exterior walls and roofs covered with cedar shingles. One spring we were opening the place up and I saw this big gaping hole at the top of a wall when I entered the cabin. I got a ladder and checked it from the outside – sure enough, a pileated had chopped big square hole into it. When it broke through it must have been pretty surprised. "Wow – a hollow tree with
furniture!"
Just a note, Tai Chi – those woodpeckers aren't hungry for your siding, they're going after insects. You may want to do a little exploration and see if there are carpenter ants behind the siding. Forego the shotgun and put up a suet feeder!