Squirrels shoving nuts into the box. They are going to forget where they put them.
Critters can seriously mess up things. The longest I ever went without power was because of squirrels playing around a major transmission station. Also, my AC started leaking like hell this summer, and I was about to buy a new one when I noticed bird seed shells all over the top and some had fallen into some small grooves. The guy next door had put a feeder on the side of his unit outside his bedroom window and the birds (
and squirrels)would perch there munching and spitting shells all day long. Into MY air conditioner. They finally clogged up the drainage pipe.