They hammer to stake out their territory. If they are looking for food they'll select a rotten spot on trees where there are worms to get. But when they start on power poles and houses, that is a territorial thing.
A 22 with bird shot works pretty well. Once they start on a house, they wont quit till they either get chased away by another wookpecker or they are done in.
A pileated sounds just like someone chopping with an ax. A yellow hammer (flicker) sounds like a air hammer going. I have seen them both drive a hole nearly right through a power pole. If you put tin over it, they'll just pound on the tin.
If you have a suggestion for quieting Mocking birds, please post. Something short of lethal if you would.
On second thought, lethal is okay. There are some summer nights I wouldn't mind sleeping.