Is This the One?

This morning I watched a pair of Tree Swallows and a pair of Eastern Bluebirds negotiate which nest box they would move into.  One can only imagine what they were saying to each other.  The females went in and out of the openings, and the males seemed to prefer to sit on top.  The two boxes were only a few feet apart.  It looked to me like they were going to end up as neighbors.  I have placed the bluebirds as an extra.