The main food for Pileated Woodpecker is the larval stage of Carpenter Ants; the tree must have been infested. Don't worry about the tree being damaged by the Pileated Woodpecker, Carpenter Ant invasion has already sealed it's fate.
Perhaps you could share a photo of the tree.
Yep, they do a number on a tree. Had a big healthy looking spruce fall over a few years ago. Turned out the carpenter ants had hollowed the center right out.