Little bluebird in my backyard

My parent's backyard is more or less rife with wildlife. While Holly and I were there over Christmas, there was a large flock of bluebirds that would come and go with some regularity. They were fond of the birdbath on our back deck, and this guy was clearly having a good time. There were often 30-50 bluebirds that would be taking turns at this and other birdbaths in the back yard.