Why wood a Redheaded woodpecker be pushing up your asphalt shingles and going like a jackhammer?

Woodpeckers eat insects that hide under tree bark. For some reason this particular woodpecker thinks that there are some juicy, delicious insects hiding under your asphalt shingles. And maybe there are.

Probably not so, I was told that a they are territorial, and while eating they peck slower but when marking territory they peck loud and fast, using the roof, enhances the noise he intends to make. Like I said this is what I have been told, Any confirmation would be great.