Hole Created by Pileated Woodpecker (Dryocopus pileatus)
These woodpeckers make impressive, often large, rectangular excavations in trees and rotting wood. They make these holes while in pursuit of carpenter ant tunnels, which is the woodpecker’s primary food source. They also use their long, barbed tongues to extract beetle larvae or termites from the wood.
They are very loud birds that I often hear in the forest, but rarely see. However, the signs that they have been there are unmistakable, as you can see in this picture. I'm not sure what kind of tree this was, but it was a conifer - maybe Eastern Hemlock (Tsuga canadensis).