By HENRY FOUNTAINNY TIMES
To reach elite status in many airline frequent-flier programs, you have to log at least 50,000 miles in the air in a year.
Somewhere in Greenland there’s an Arctic tern that could qualify.
Arctic terns have a reputation as long-distance travelers, migrating to the Southern Ocean from breeding grounds in the Arctic. Researchers have suggested the round-trip distance might be as much as 25,000 miles.
But those were only estimates. While location-tracking tags have been used with large birds like albatrosses, Arctic terns, at less than four ounces, were too small to carry them.
Now Carsten Egevang of the Greenland Institute of Natural Resources and colleagues have devised a miniature data logger that, at 1/20th of an ounce, is light enough. It records light intensity, using the timing of sunrise, sunset and length of twilight to determine latitude and longitude.
In The Proceedings of the National Academy of Sciences, the researchers report on the journeys of 11 terns fitted with the devices. The birds, which began their trips in Greenland or Iceland in August, took two routes south, some hugging the African coast and others crossing from West Africa to Brazil to follow the South American coast. They stopped for about three weeks in the mid-Atlantic east of Newfoundland, a rich feeding zone.
Once they reached the Southern Ocean, they spent four months flying primarily east and west, again in areas that are rich in food. They returned in May and June having traveled, on average, about 44,000 miles. One tern totaled 50,700 miles, which is the longest animal migration ever recorded electronically.
