The Gannet, or more correctly the Northern Gannet, is a large seabird with a characteristic spectacular plunge diving habit. Scotland holds half of the world population of Northern Gannet in 14 colonies; the biggest colonies are on St Kilda, the Bass Rock in the Forth Estuary, Ailsa Craig in the Clyde Estuary and Hermaness in Shetland. It is a summer visitor to Scotland although its return arrival can be as early as January with good numbers retuned by March. During the breeding season birds will travel many miles from the colonies in search of good feeding.