Then last Saturday morning I looked out my window and saw three Tree Swallows sitting on the wire. They stayed and stayed. Finally, one decided to check out the real estate. It perched on the box and looked up and down and all around for a long time. It studied every dimension of the outside of the box and the surrounding area.
They flew from the wire to the house over and over. For the last three and one half days they have been repeating this behavior. Yesterday, an American Goldfinch got too close to the house, and one of the Tree Swallows flew down and drove it off. They seem to have taken some ownership of the house already.