Ecological notes: I watched the nuthatches "drumming" on the trees - they seemed to be prying bark off to get at little insects underneath. I watched them on super cold days doing this and wondered how much of their behavior is based on blind luck. Since insects wouldn't be moving around (temperatures where subfreezing) then they couldn't hear them. They'd have to smell them (most birds can't smell), see them (they were peeling the bark off to get underneath where the bugs were), see sign of their presence (like entry holes, feeding sign etc, indicating the birds are awesome trackers), or rely on dumb luck that peeling off enough bark will ultimately yield enough calories to stay warm.
Where: Silver maple in my yard