If, as Thoreau says, the bluebird carries the sky on its back, the Indigo Bunting may sometimes be carrying storm clouds. These common open space birds are now arriving back in NC from their tropical winter homes and the males have dressed for the occasion. During the winter, both males and females are primarily brown, nondescript birds. But for their spring breeding season, males molt into our only all blue-colored bird. But, the blue we see in feathers is not from a pigment, like, say, the red in a Northern Cardinal. Rather, blue in birds is a structural color – the blue we see is caused by the way light is refracted and reflected in the structure of the feather itself. And, especially for the Indigo Bunting, it needs sunlight hitting it at the right angle for us to see that brilliant blue color. Otherwise, it looks brown or even black, much like a storm cloud on the horizon.
These are said to be one of the most abundant songbirds in the East since their preferred habitat, brushy edges like in power line right-of-ways, etc., are often created and maintained by human activity. I see them every year along the power line corridor, but I hope to spend a little more time this summer listening for their distinctive calls (the male sings all day, even in the heat of summer) and enjoying their brilliant blue attire.