Arctic tern, Sterna paradisaea.

Arctic Tern, Sterna paradisaea

The arctic tern is one of the greatest travellers in the animal kingdom. It has a circumpolar distribution, and with a range that extends southward into the northern temperate zones of North America and Europe. Its lengthy migration takes it to its winter spots in Antarctica – a journey of at least 16,000 km! Some birds travel much farther. For example, those birds that breed in Labrador and Newfoundland first cross the Atlantic to Europe in the fall, and then begin their migration to Antarctica from there. Many birds take detours following the trade winds; although this lengthens the distance, it allows them to conserve energy by soaring.

The arctic tern is similar in shape to other terns, with a slim, streamlined body, pointed, elbowed wings, a forked tail and a spearlike bill. Its body and the rear half of its underwings are white, while the rest of its wings and its back are pale grey, except for a splash of black under the wingtips. It has a jet black cap and a bright red bill. This tern is about 35-43 cm in length, smaller than a crow. In the winter, its bill becomes dark red or black and its black cap is confined to the back of its head, while its forehead becomes white.

Arctic tern eggs.

In the Arctic summer, these birds build nests in shallow depressions in the ground, lined with a few flat, smooth stones, or bits of whatever vegetation they can find. Their two eggs are so well camouflaged that they are difficult to see, even from a metre away! The birds incubate their eggs for about three weeks, and the young leave the nest four weeks after they hatch.

Terns eat insects, aquatic invertebrates and small fish. While winter blankets the Arctic, terns hunt throughout the summer Antarctic pack ice for fish and plankton. They have no real home base during this season, but instead travel constantly in search of food. Because arctic terns divide their time between the two poles, experiencing the summer midnight sun of each, these birds see more hours of daylight than any other animal!