I have spent some time (not a lot, but not none) trying to make a happy home for bluebirds. First of all, I like bluebirds. But I am also interested in any kind of no-pesticide insect control, particularly around the cow. For reasons that are too involved but trust me, they were reasonable, our round pen is actually in the smaller pasture that also has the cow's milk stand & stall. & although the gates between this pasture & the larger one are almost always open, this area around the round pen & the milk stand is always where the bugs converge.
So, bluebirds. Or purple martins, which is who we actually expected. In the tradition of "if you build it, (t)he(y) will come", we put a potential martin house on the highest post of the round pen & within what seemed like moments, we had bluebirds checking it out.
This particular photo was taken early in the morning when I went out to deal with our hens. The whole time I had a feeling I was being watched & when I looked, there he was on the fence between the small pasture & the backyard - the round pen is in the background,