Keep flying…

by Yule Heibel on September 22, 2007

It’s busy around here, which is why posting to the blog is sparse (to put it kindly).

But the other day — really in passing, the way a bird might fly past the window, and the window is your life as you’re standing there and living it, except I was moving and the window was holding still, so I’m kinda wondering about what my life is up to if it’s not the window, and …oh, well never mind! — anyway, the other day I heard about a bird called the godwit (what’s in a name, you ask? …sometimes everything, perhaps?), a female godwit named (as it were) E7, which was electronically tagged and proven to have flown from New Zealand to Alaska, where it almost certainly hatched out some young during its 5 week “lay-over,” after which it took wing and flew non-stop, from Alaska, all the way back to New Zealand.

I don’t know about anyone else, but this just floors me. Brings me right down to earth. Clips my wings, in a manner of speaking.

We’re talking about a bird — read: relatively tiny creature — capable on its return trip of flying 11,500 km …non-stop. As in: without a single touch-down anywhere, without stopping for food or water, without skipping a single (wing)beat… For eight days straight. For eight days, this bird didn’t stop. It puts a whole new spin on the old “she eats like a bird” comment…

Here are quotes from a couple of articles on E7’s migration:

“The Bar-tailed Godwit is one example among hundreds of migratory bird species which undertake awe-inspiring journeys every year,” said Dr Vicky Jones, BirdLife’s Global Flyways Officer. “Migrant birds rely on chains of traditional stop-over sites at which they can re-fuel and rest before embarking on the next leg of their journey.”

What’s interesting is that this particular godwit didn’t use any stop-overs, so perhaps this one is an exceptional athlete. Whatever, it underscores the need for countries to cooperate, to make sure that stop-over sites are available and not degraded beyond use. Whether non-stop or with lay-overs, migration is amazing.

On the way from New Zealand to Alaska to breed, E7 did use a lay-over, but not on the return from Alaska to New Zealand:

Ecologist Phil Battley, of Massey University, told the New Zealand Herald the bird, known only as E7, first flew 10,200 km to the Yalu Jiang Nature reserve in China’s Yellow Sea where she spent five weeks refuelling before flying another 7,300 km to breeding grounds in Alaska.

He said she spent two months at the Yukon-Kuskokwim Delta, where she was almost certainly breeding, leaving about mid-July before going to mudflats on the edge of the Yukon Delta where she refuelled again, ‘getting nice and fat’ until the end of August.

Battley said her southward flight from Alaska to New Zealand was thought to be the longest non-stop migration of any bird.

‘She had the option to fly down to the Alaskan peninsula and take off from about 500 km further south but she didn’t do that,’ he said. ‘This indicates the long journey is not such a problem to her.’

E7 did all this without eating or drinking anything during the actual migration:

“We were pretty impressed when she did 10,200km on the way north,” says Massey University ecologist Phil Battley. “And the fact that she can now do 11,500km… it’s just so far up from what we used to believe 10 years ago when we were thinking a five or 6,000km flight was extremely long. Here we’ve doubled it,” adds the New Zealand coordinator of what is an international study.

For researchers, tracking the second leg of E7’s journey was a bonus – her implanted satellite tag kept working well past its expected cut-off date.

“If you’re trying to confirm how far birds fly and whether they are making stop-offs, it’s only now with the technology being small enough, you can do this remotely. Otherwise we’d still be using educated guess work,” Dr Battley says.

And that means the researchers now know that the godwits really are the champions of avian migration. Unlike seabirds, which feed and rest on their long journeys or swifts which feed in flight, the godwits make their long journeys without feeding or drinking.

It’s still a real mystery how E7’s young — and the young of all the other godwits who came to breed in Alaska this past summer — will manage to find their way to New Zealand once they’ve matured. Yes, like salmon, these comparatively tiny beings have to cross incredible distances to fulfil biological destiny, as it were, and like salmon, they do it without “parental” or “adult” supervision or guidance. So what is it that shows them the way? Electro-magnetic fields in the earth? Navigation by astral maps? Some homing signal you or I can’t hear, but they can?

This New Zealand newspaper editorial asks the question, too, and sums up by concluding that maybe the tiny godwit — by not yet revealing all its secrets — can take our hubris down a notch, too:

The study of that admirable bird is essential. First, because it is endangered. Over millennia the rich mudflats of predator-free New Zealand has offered an abundant sanctuary. Human habitation, with its cats, dogs and stoats, has taken its toll. We need to understand the bird to ensure it survives.

Second, if we unravel the secret that not only sends and guides the godwit back and forth but also sustains it on its epic flight, it may be to our own benefit: We may have much more to learn from the birds than flight technology.

And last, the study of the godwit gives wing to the imagination. The contemplation of the unknown or unknowable (part of us may wish the bird’s magic is never revealed) is a necessary antidote to earthbound life. That we are able to be confounded, humbled and inspired by a tiny bird that can do so much that we can’t, is worth appreciating for itself.

It’s kind of interesting to think that getting shifted from the centre of things by a small critter (a bird), we deconstruct hubris and reconstruct imagination. Just a bit, just enough for a slight leap into some perfectly working creature’s flightpath…

PS: On a related note, an article by the always terrific Jonah Lehrer, Eggheads: How bird brains are shaking up science, in the Boston Globe.


Doug Alder September 23, 2007 at 1:14 pm

It’s interesting that it takes a different route back than it did coming. I’m guessing it has something to do with the earth’s rotation (like space launches go west to east to take advantage of rotation thereby lessening the energy needed to reach orbit)

mpb September 24, 2007 at 8:53 pm

Doug, It seems it is actually something to do with flying a great circle route (least distance) with a changing bearing (rotating body, earth). I was going to link various posts I have about these separate topics with what I found out about plotting air routes for bush planes in the same area of Alaska. More recently than this article it has been found that many birds also use polarized light for navigation, especially on overcast days. (polarized light is north-south, even if the magnetic north wanders)


But how do these Arctic migrants accomplish the demanding task of computing great-circle courses? It seems they apply an intelligent trick. Mathematicians have worked out that if one uses a time-compensated sun compass without resetting one’s internal clock while traveling across different time zones (longitudes), the resulting curved route would look like an orthodrome (9). Apparently, it is not only mathematicians who realized that navigating by the sun with the internal clock kept out of phase with local time automatically results in a flight route that is roughly parallel to an orthodrome.

Comments on this entry are closed.

Previous post:

Next post: