Follow up comment.
The young have fledged now, at least three days ago. All is quiet in the orchard again.
Except for the deer munching on my grape leaves, and the rabbits, and the many birds including frequent plaintive cries of the flicker who's taken up nearby residence!
I went to the tree where the woodpeckers have had their residence. We had watched the female throw out mouthfuls of splinters when she enlarged the space back in April.
We marveled how the adult could go inside the smallish tree, maybe 8-9" diameter with the young. How do they turn around in there? They go in head first and exit facing out, sensibly. Plus two kids? Sounds like time for a room addition.
Yesterday I approached the abandoned tree. Nobody home anymore. The closest I had come was about twenty feet while photographing them, after several weeks of getting them accustomed to our presence. We work in our garden daily, which is only thirty feet away or I would not have been noticing this whole event under my own nose.
I tapped on the trunk. It's hollow about a foot down from the entrance. This old apple tree, probably thirty years or more old, has been nearly hollowed out inside. I've lived here ten years and when I got here nobody had pruned for fifteen years before that. It's a smallish tree that used to give me decent yields of red, wine flavored apples, but now it's raised a family of woodpeckers. A great way for this little patch of earth to carry forward another generation.