I have had other visitors at my duck box houses besides ducks, like a bee, mouse, squirrel, chickadee, nuthatch, bluebird and recently a northern flicker. I have had some dead trees blown down in the last storm, so I wonder if the flicker’s prior nesting site has fallen down and is looking for a new home. But the opening on the duck box is much bigger than the size they create in trees.
Northern Flicker