What could these two possibly have in common?
They were both addicted to whatever elixir this tree produces. I first noticed the squirrel licking the tree, then saw flies on it and then the sapsucker showed up, who had made the pattern of gouges over time.
And I really do mean addicted: the woodpecker's desire for sap overrode its life-protecting impulse to flee upon seeing me. Initially, when I was about 30 feet away, it was spooked by my presence. After gradually creeping closer over an hour, I was about six feet away from it. The bird was so enthralled by the tree's excretions that it didn't mind me or my camera shutter clicking.