Cormorants are medium-to-large seabirds and all species are fish-eaters, catching the prey by diving from the surface. It nest in colonies around the shore, on trees, islets or cliffs. They are coastal rather than oceanic birds.After fishing, cormorants go ashore, and are frequently seen holding their wings out in the sun. All cormorants have preen gland secretions that are used ostensibly to keep the feathers waterproof.