BE AMAZED!

I’m not exactly a birder, but my late brother was a falconer and interested in birds all his life, and because of that I have a more-than-passing interest in birds. So when a friend who is also interested in birds sent me the news that a juvenile bar-tailed godwit, a very pretty sort of wader, has just flown 8,425 miles from Alaska to New Zealand, trans-Pacific, non-stop, and in eleven days and one hour for an average speed of about 32 mph, I say “What an incredible feat!”

Being previously unaware of the existence of the bar-tailed godwit, I decided to find out some more and turned to Der Google. It turns out on further research, that the other bar-tailed godwits now sitting in the trees in New Zealand who have heard this news responded “Meh.”

That’s because on September 14, 2007, it was learned a female godwit did the flight in nine days. This was also the first time humans learned that these birds fly direct from Alaska to New Zealand. It had been thought before that they wended their way down the Chinese coast, then through Indonesia, stopping along the way. Nobody thought they could fly direct.

Some 70,000 godwits make the epic journey from their northern summer breeding grounds in Alaska down to New Zealand each September, before flying all the way back the following March. They like the fact there are no predatory falcons there, which give the young that are born the chance to grow to sufficient maturity to make the flight. A godwit makes their first flight at an age of approximately 3-4 months. Incredibly, it is possible that three-month-old godwit juveniles fly their nonstop maiden voyage without adult supervision. That has yet to be confirmed.

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, flapping their wings continuously. It is so extreme, and so far beyond what researchers knew about long-distance bird migration, that it has required new investigations.

Sea-faring Polynesian cultures knew about the migrations long ago and used the birds to assist in navigation. (So much for GPS)

The known distance record for a godwit migration is 13,000 kilometers, or nearly 8,080 miles. It was set last year by an adult male bar-tailed godwit with a tag code of 4BBRW that encountered inclement weather on his way to New Zealand and veered off course to a more distant landing in Australia. He had flapped his wings for 237 hours without stopping when he touched down.

Other birds stay aloft for long periods using a technique called “dynamic soaring;” godwits power themselves by continuous flapping, which takes far more energy.

Distances vary, but all told, in a year, the godwits cover some 30,000 kilometers, or nearly 18,720 miles, because they take a less direct route to return north in March. They fly nonstop from New Zealand to China’s Yellow Sea and its rich tidal flats, where they refuel, and then return to Alaska. And they are proficient at the incredibly risky endeavor; the survival rate is more than 90 percent.

The energetics of their nonstop migration are also a conundrum. Current models say the birds should conk out after three or four days, yet they fly for more than a week. “We can’t explain the physiology that allows them to do this,” Dr. Guglielmo said. “We know what the energy costs should be from wind tunnel experiments, but when we try to use our models, the energy costs we know they used are much lower.” The birds use half or less of the energy expected.

One answer may be that the birds can lower their metabolic rate on these journeys, burning far less energy than they would for other kinds of flying. “Are they going into a suspended animation state when they are doing these monster flights?” Dr. Guglielmo asked. “I don’t think they are in a normal physiological state when they are doing this,” he said, adding they might enter into a state like something akin to “marathon runners getting into the zone.”

“It’s not really like a marathon,” said Christopher Guglielmo, an animal physiologist at Western University in London, Ontario, who studies avian endurance physiology. “It’s more like a trip to the moon.”

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.

These are not big birds! They’re about the size of one of those pesky crows in your back yard.

Crossing a nearly featureless Pacific Ocean without navigational cues required an internal map to define position and a compass to tell direction. The birds find their way back to the same specific sites at the end of their flight, something they do for each of the 15-20 years of their lives.

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.

So, today, in the midst of everything else, be amazed at what a little bird that could perch on your wrist can do.

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