There's a 'squirrel tail' tree in the Garden (where I work). Apparently an elderly or ill squirrel crawled into a favorite hole, leaving only an emergent tail to mark a final resting place.
But looking for a red-shouldered hawk nest nearby (the squirrel tail tree was a landmark), I saw a pair of squirrels scampering into a hole higher up in the tree.
They poked their heads out enough for some decent photos.
It was nice to see squirrels taking advantage of cavities in trees, for nesting spots.