The Arctic tern breeds in the Arctic and is the only bird known for regular migration between the geographic polar regions.
Arctic terns breed in the far north of Europe, Asia, and North America, then travel south to Antarctic waters for the austral summer. Because the two polar summers occur at opposite times of year, the birds can experience more daylight than almost any other animal. Their annual route is commonly described as roughly 40,000 kilometres, although tracking studies show that individual routes can be substantially longer.
The species is not the same as the common tern, which has a shorter and more southerly range. Arctic terns are medium-sized seabirds with a red bill, pale body, and deeply forked tail. Their migration is one of the clearest examples of a journey linking the planet’s two high-latitude ecosystems.