Thus far I have one male bluebird working to build a home inside one of the nest boxes and perhaps two. The tree swallows changed their minds as they did two years ago when they were around for two days. I hope someday to get a pair to stay and mate as the male is a beautiful green on top and white underneath and just shines. As I am always cutting grass or in the gardens, they must not like the activity. The bluebirds, and certainly the wrens (who will nest next) could care less. The wrens are quite comical and the male's beautiful song in attempting to garner a female to join him in one of my birdhouses is special with a cup of coffee in the morning. Life is good.