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Arctic TernOnly a handful of Arctic terns nest in Norfolk. To most observers they are a spring and autumn passage migrant. Breeding grounds are in general to the north of common terns. In the far north Arctic terns nest on bare rocky islands and stacks. The birds fish near large icebergs, in ice-filled bays and in tide-rips - by night as well as by day. It is the most northerly breeding tern in the world. Each autumn flights of Arctic terns from northern Europe and Siberia journey south, soon entering the North Sea and passing the East Anglian coastline. These birds enjoy more daylight in the course of a year than any other creature. During our winter they spend another summer just north of the Antarctic pack-ice. Distances covered by Arctic terns are astonishing and are more extensive than those of any other bird. Hardly any passage of Arctic terns has been noted by birders on the USA's east coast. When the first transatlantic recoveries were reported, it was realised that the terns breeding in Canada, northeast USA, Greenland and Spitsbergen were crossing the Atlantic on wind-aided westerlies before turning south down the western seaboard of Europe. Here the flights converge with travellers from northern Europe. But why should these birds risk crossing the north Atlantic at all? Surprisingly, it has been calculated that the influence of tides and air currents the route to South America and ultimately Antarctica by way of Africa is much better. Arctic terns are long-lived. Many ringed ones have been re-trapped 10 or even 20 years later. Oldest examples attained 27 and even 34 years of age. By Michael J. Seago
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