The Arctic Tern flies and glides through the air, performing almost all of its tasks in the air. Arctic terns nest once every one to three years (depending on its mating cycle). Once it has finished nesting it takes to the sky for the longest migration made by any bird; migrating from its northern breeding grounds along a winding route to the oceans around Antarctica and back, a round trip of about 70,900 km (c. 44,300 miles) each year.