Maybe the pair of bluebirds will come back.  Last year they checked out our bluebird nesting box in the backyard.  My wife spotted them out the kitchen window but the next day the bluebird box fell.  They never came back.  I did notice the nesting box fell again but I put it up more securely the next day.  It just turned March so it is early in the season so let us see if any bluebirds check out the spot.  And better yet raise a family while we watch.