The Arctic Tern (Sterna paraisaea) is a seabird of the tern family Sternidae. This bird has a circumpolar distribution, breeding colonially in Arctic and sub-Arctic regions of Europe, Asia, and North America (as far south as Brittany and Massachusetts). The species is strongly migratory, seeing two summers each year as it migrates from its northern breeding grounds to the oceans around Antarctica and back (about 24,000 miles) each year. This is the longest regular migration by any known animal.