02053nas a2200229   4500008004100000245008000041210006900121260001200190520135800202653001401560653002001574653002401594653001301618653001301631100002101644700002401665700002601689700002001715700001901735700002301754856004601777       2010                        eng d00aTracking of Arctic terns Sterna paradisaea reveals longest animal migration0 aTracking of Arctic terns Sterna paradisaea reveals longest anima  cJanuary3 a10.1073/pnas.0909493107 The study of long-distance migration provides insights into the habits and performance of organisms at the limit of their physical abilities. The Arctic tern is the epitome of such behavior; despite its small size (<125 g), banding recoveries and at-sea surveys suggest that its annual migration from boreal and high Arctic breeding grounds to the Southern Ocean may be the longest seasonal movement of any animal. Our tracking of 11 Arctic terns fitted with miniature (1.4-g) geolocators revealed that these birds do indeed travel huge distances (more than 80,000 km annually for some individuals). As well as confirming the location of the main wintering region, we also identified a previously unknown oceanic stopover area in the North Atlantic used by birds from at least two breeding populations (from Greenland and Iceland). Although birds from the same colony took one of two alternative southbound migration routes following the African or South American coast, all returned on a broadly similar, sigmoidal trajectory, crossing from east to west in the Atlantic in the region of the equatorial Intertropical Convergence Zone. Arctic terns clearly target regions of high marine productivity both as stopover and wintering areas, and exploit prevailing global wind systems to reduce flight costs on long-distance commutes.10amigration10amigratory-birds10asatellite-telemetry10aseabirds10atracking1 aEgevang, Carsten1 aStenhouse, Iain, J.1 aPhillips, Richard, A.1 aPetersen, Aevar1 aFox, James, W.1 aSilk, Janet, R. D.  uhttp://dx.doi.org/10.1073/pnas.0909493107