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Researchers marvel at the bird’s record-holding migratory flight of 7,000 or so miles from Alaska to New Zealand at this time of year. No eating or refueling along the way.
Tens of thousands of bar-tailed godwits are taking advantage of favorable winds this month and next for their annual migration from the mud flats and muskeg of southern Alaska, south across the vast expanse of the Pacific Ocean, to the beaches of New Zealand and eastern Australia.
They are making their journey of more than 7,000 miles by flapping night and day, without stopping to eat, drink or rest.
The godwit’s epic flight — the longest nonstop migration of a land bird in the world — lasts from eight to 10 days and nights through pounding rain, high winds and other perils. It is so extreme, and so far beyond what researchers knew about long-distance bird migration, that it has required new investigations.
Other birds do stay aloft for long periods using a technique called “dynamic soaring,” while godwits power themselves by continuous flapping, which takes far more energy.
The journey of these ultra-endurance athletes is made possible by a suite of adaptations.
Godwits are avian shape-shifters, endowed with an unusual plasticity. Their internal organs undergo a “strategic restructuring” before departure. The gizzards, kidneys, livers and guts shrink to lighten the load for the trans-Pacific journey. Pectoral muscles grow before takeoff to support the constant flapping the trip requires.
They are built for speed, with aerodynamic wings and a missile-shaped body. The only baggage the birds carry is fat, by gobbling up insects, worms and mollusks to double their weight from one to two pounds before embarking on their trip. Because godwits directly use fat to fuel their flight, Dr. Guglielmo in one paper called them “obese super athletes.”
The godwits probably rely on several cues for navigation, especially the sun and stars. Some experts believe that they may be able to sense magnetic lines on the planet through a process called quantum entanglement.
The birds also possess an uncanny knack for weather forecasting.
“They know what conditions to leave on that will not only provide wind at the start that is favorable, but throughout their entire flight,” Dr. Gill said. “They can piece the puzzle together in terms of what the conditions are in Alaska and between there and Hawaii, between Hawaii and Fiji, and between Fiji and New Zealand. How migration abilities are passed on to the next generation — whether genetically or learned or a combination — is still unknown.
