Sunbathing is a way for many species of birds to kill parasites.
A number of species have decided that a particular spot in my yard is a great place to sunbathe. (So far: a robin, another robin, yet another robin and a blue jay, a starling, a cardinal, and I’ve seen a grackle doing it but didn’t get a picture of it).
Before I learned what they were doing, I thought these birds were likely in distress because they were fluffed out with their mouths open and eyes half-closed and/or wings spread, which is how they often look when they have neurological injuries (after colliding with windows, for example), and they were doing it in the full sun, when there are several bird baths nearby.
Would it be worthwhile to start a project of sunbathing birds in case anyone is studying this phenomenon?