A female bar-tailed godwit, a large, streamlined shorebird, has touched down in New Zealand following an epic, 18,000-mile-long (29,000 km) series of flights tracked by satellite, including the longest non-stop flight recorded for a land bird.
The U.S. Geological Survey's Alaska Science Center tracked the odyssey of the bird as part of an ongoing collaborative effort with colleagues in California and New Zealand. The scientists were hoping to better understand potential transmission of avian influenza by migratory birds.
The bird, dubbed "E7" after the tag on its upper leg, was captured along with 15 other godwits in New Zealand in early February 2007. There each bird was fitted with a small, battery-powered satellite transmitter. USGS scientists hoped the transmitters' batteries would last long enough to track the birds' northward migration to Alaska.
On March 17, E7 departed Miranda on the North Island of New Zealand and flew non-stop to Yalu Jiang, China, completing the 6,300-mile-long flight in about eight days. There she settled in for a 5-week-long layover before departing for the breeding grounds.
On the evening of May 1, she headed east out over the Sea of Japan and the North Pacific, eventually turning northeast towards Alaska, crossing the end of the Alaska Peninsula en route to her eventual nesting area on the Yukon-Kuskokwim River Delta in western Alaska. This flight was also accomplished non-stop, covering some 4,500 miles in five days.
E7 was then tracked to the coast of the Yukon Delta where she joined other godwits preparing for their return flight to New Zealand.
On the early morning of August 29, she took off southeast back across the Alaska Peninsula, went out over the vast North Pacific and headed towards the Hawaiian Islands. When less than a day's flight from the main Hawaiian Islands, she turned southwest, crossing the Hawaiian Archipelago over open ocean 125 miles west of Kauai, heading towards Fiji. She crossed the dateline about 300 miles north-northeast of Fiji, and then appeared to fly directly over or slightly west of Fiji, continuing south towards New Zealand.
In the early afternoon of September 7th she passed just offshore of North Cape, New Zealand, and then turned back southeast, making landfall in the late evening at the mouth of a small river, eight miles east of where she had been captured seven months earlier.
The last leg of E7's journey is the most extraordinary, entailing a non-stop flight of more than eight days and a distance of 7,200 miles, the equivalent of making a roundtrip flight between New York and San Francisco, and then flying back again to San Francisco without ever touching down.
Since they are land birds, godwits like E7 can't stop to eat or drink while flying over open-ocean. The constant flight speeds at which E7 was tracked by satellite indicate that she did not stop on land.
Godwits do not become adults until their 3rd or 4th year and many live beyond 20 years of age. If 18,000 miles is an average annual flight distance, then an adult godwit would fly some 288,000 miles in a lifetime.
The study that recorded E7's epic flight is a collaborative effort led jointly by USGS and Point Reyes Conservation Science, with cooperators from Massey University and Miranda Shorebird Centre, New Zealand, and The Global Flyway Network. The project is funded by the David and Lucile Packard Foundation, the USGS, Alaska Science Center, and the U.S. Fish and Wildlife Service.
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