As it turns out, I need not have been concerned about the housing choice of my little red squirrel. He/she has stuffed the box so full of materials that there is not even room for a screech owl to climb inside, let alone find a victim in all that rubble. Sorry I ever doubted your wisdom, little buddy!
A brief pause between grocery runs.
Squirrelly hoard for winter enjoyment.
After nibbling on an apple ...
... the fruit is wedged among nearby branches to dry.