House-Hunting?

This flicker entered my (unused) nesting box and proceeded to throw out some of the shavings and sawdust I had filled it with. "Excavating a cavity is an essential part of the Flicker’s mating behavior. " -- Washington Department of Fish And Wildlife.

It definitely isn't the mating season, so I don't know if this has any significance. Maybe the male is hoping to find a naive female.