In the past, they nested in the yard eight different summers.

I've read that volunteers take care of a number of bluebird houses in a nearby park. Maybe these guys are descendants of that group.

Most of the trees in my yard are still pretty small. But some of the neighbors have large native trees that probably produce a good number of caterpillars. I'm working on adding many more native plants. Hopefully, together they will help make a stable supply of food for any baby bluebirds in the neighborhood.