Vultures are natures sanitation workers. Their main diet is carrion, picking clean dead carcasses before they begin to rot. They have bald heads and necks which help to keep them clean when dealing with larger prey. There are also some speculations that the bald head and neck is also used for thermoregulation. These birds are the oldest of the diurnal raptors. There are two kinds of vultures, new world and old world. The two vultures that are found in Illinois include the black vulture and the turkey vulture.