The Common Tern breeds in suitable habitat throughout Europe, Asia, North America and West Africa. Outside the breeding season it migrates in a leap-frog manner with birds from south-west Europe wintering in West Africa north of the Equator, birds from Britain wintering either side of the Equator and birds from Scandinavia wintering in southern Africa.
They feed mainly on salt-water fish which they catch by plunge-diving often after hovering. The fish is swallowed immediately on reaching the surface of the water unless it is being taken to a mate or young in which case it is held crosswise in the bill as can be seen in the second photo.
It is sometimes difficult to differentiate between Common Tern and Arctic TernSterna paradisaea. Several points are visible in the first two photos: the Common Tern has a black tip to its red bill (most of the time), its bill is longer and it has longer legs, and its upper wing has a dark wedge which is less obvious in the spring. Both species are present in the third photo with Common Tern to the left and Arctic Tern to the right.