Arctic terns feed from the water while on the wing. In a lifetime spent in perpetual summer, the Arctic tern flies 44,000 miles from pole to pole each year, flying between its breeding grounds in Greenland and the Weddell Sea on the shores of Antarctica in the far south. The British Antarctic Survey found that the birds do not immediately head south from Greenland, but first spend almost a month at sea, in the middle of the North Atlantic, before continuing down the coast of north-west Africa. Around the Cape Verde Islands, the researchers were surprised to find that about half the birds carried on south along the African coast while the rest crossed the Atlantic to follow a parallel route down the east coast of South America. All the terns studied escaped the northern winter by flying to Antarctic waters, where it is summer at that time of year. On the return trip, they again did not take the shortest route, but traced a giant ‘S’ shape. The distance each bird flew during its lifetime equaled three round trips to the Moon – or more than 1.25 million miles.