The Arctic Tern also has the longest regular migration by any known animal with 70,900 km ( c. 44,300 miles ) each year . The species is strongly migratory , seeing two summers each year as it migrates 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 . This is by far the longest regular migration by any known animal .