The Common Tern (Sterna hirundo) is a seabird of the tern family Sternidae. This bird has a circumpolar distribution, breeding in temperate and sub-Arctic regions of Europe, Asia and east and central North America. It is strongly migratory, wintering in coastal tropical and subtropical regions. It is sometimes known as the sea swallow. Its foreign names are, in French: Sterne pierregarin; Spanish: Gaviotin comun (South America) or Charran comun; Portugese: Trinta-réis-boreal (Brazil) or Garajau-comun (Azores); German: Flusseeschwalbe. Like all Sterna terns, the Common Tern feeds by plunge-diving for fish, from a height of 1-6 m, either in the sea or in freshwater lakes and large rivers. It usually dives directly, and not from the "stepped-hover" favoured by Arctic Tern. It commonly forages in flocks (though in inland populations, individuals often forage singly on in pairs). The prey fish are 5-15 cm long. Occasionally it can also take insects, crustaceans, and dead fish. The Common tern forages up to 20 km away from the breeding colony, usually within 1 km of the shore.