I was just watching the birds and saw a mourning dove spread out with one wing flat out on the ground. I was concerned but she flew away when I approached. Do you have any idea what it was doing? Could something be wrong? ~ Augusta, Michigan
Instinct to sunbathe even when already heat-stressed, supports the idea that it’s not always to warm the body. Like humans they probably enjoy a few rays but their main reasons for sunning must be to keep their feathers in top shape. Some ways birds maintain feather quality is through water, dust, and sun bathing.
Most birds have a preen gland or uropygial gland at the base of the tail. With their beak, birds realign the barbs correctly, remove any dirt or parasites and apply preen oil. If the bird sunbathes the oil is exposed to the ultraviolet light from the sun. Then the uropygial gland secretions convert to an active form of vitamin D which is ingested with the next preening. This may explain in part why some birds sunbathe.
However, doves don’t have the preen gland. Instead they grow powder down feathers that grow continuously and never molt. The barbs at the feather tips constantly disintegrate into a fine, talc-like, water-resistant powder. If you’ve ever seen a window strike by a dove, you may have seen a “ghost bird” on the glass. This is actually a tracing of the bird left on the glass by its powder down.
In late summer doves are growing new outer feathers. Like ironing our clothes, the heat of the sun might help make it easier for doves to shape their new feathers. And along with easing discomfort associated with molting, the sun may also help dislodge parasites so the bird can preen them off more easily.