Chickadee Chick Flies the Box - New Residents Move In

Last week I posted that the only remaining chickadee chick was nearly full grown and moving around the bird box. So it was not a surprise that when I checked the box today, the chick was gone. Of course, once gone they do not return to the nest or box. So sorry I have not photos.
But what was a surprise was the apparent move in by a different kind of bird. As you can see from this photo, the new residents built (or are building) a new nest on top of the previous chickadee nest. The new nest is constructed of twigs, where the chickadee nest was build of grasses and other very fine material. I'll do some research and see if I can identify likely new residents.