It was unanimously I.D'd as a WSCO although it may actually be a Goldilocks Owl since I saw an owl head sticking out of a duck box I had put up on the other side of the tree (north) in a much lower position.  That box was made out of scrap wood too, a drawer from an office desk.  Originally I was concerned about having duck boxes near each other but another wood duck lover has 4 or 5 in close proximity on his property and he told me the ducks don't seem to care.