The Arctic tern, a slender, graceful relative of the gull, makes possibly the most spectacular migration of any bird on Earth. Each autumn, the bird, which is only about 350 mm (14 in) long, leaves its breeding grounds in northern Europe, North America and Greenland to fly halfway round the world to the Antarctic Circle for the southern summer.
Because Arctic terns do not fly the shortest route, but take a path that takes advantage of following winds, they make a round trip of over 35000 km (22000 miles). As a consequence, these birds probably see more daylight than any other creature: at their breeding grounds, they experience the almost 24-hour days of the Arctic summer, and, at the opposite end of their journey, they enjoy the equally long days of the Antarctic summer.
Ornithologists fitted one newly born Arctic tern with a lightweight ring and monitored its 26-year lifetime: flying virtually from pole to pole twice a year, the bird travelled almost 1 million km (565000 miles).