A pelican is a large water bird with a distinctive pouch under the beak. They are large birds with enormous, pouched bills. Pelicans swim well with their short, strong legs and their feet with all four toes webbed. The tail is short and square. The wings are long. Pelicans rub the backs of their heads on their preen glands to pick up its oily secretion, which they transfer to their plumage to waterproof it.