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Arctic terns take break en route south for winter
[February 04, 2010] WASHINGTON (AP) -- Arctic terns heading south for the winter like to take a break for a few days off the coast of Newfoundland.
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While the little 4-ounce birds have long been famed for their migrations from the Arctic to the Antarctic and back, Tuesday's report in Proceedings of the National Academy of Science was the first to disclose their North Atlantic stopover region. Researchers led by Carsten Egevang of the Greenland Institute of Natural Resources attached tiny geolocators to terns in Greenland and Iceland. The devices, each weighing a bit more than a paper clip, recorded the position and duration of the sun, so when they were retrieved the flight path of the birds could be calculated. Analysis of the trips of 10 birds from Greenland and one from Iceland showed that after heading south they paused at a deep water area of the North Atlantic for an average of about 25 days before moving on. "This previously unknown oceanic hotspot for terns was located at the junction between cold, highly productive northern water and warmer, less-productive southern water," the researchers said. The birds then moved south, some along the coast of Africa, others along South America, until they reached the Antarctic during its summer season. The research was funded by the Commission for Scientific Research in Greenland, Greenland Institute of Natural Resources and National Environmental Research Institute, Aarhus University, Denmark. ___ On the Net: PNAS: http://www.pnas.org/ |
