Blackbirds and other thrushes often sunbathe, laid down and with wings outstretched. The sun is thought to straighten the birds feathers and help the preen oil to spread through the feathers. Some ornithologists have suggested that it may also draw parasites to the surface where the bird can remove them or that the ultraviolet light in the sunlight converts chemicals in the preen oil into Vitamin D. However, one could be forgiven for thinking that they simply enjoy it.