26 December 2012

The bar-tailed godwit can fly 11,000 kilometers. Nonstop.

As reported at Science Daily in 2010:
Every autumn the bar-tailed godwit undertakes an eight-day journey from Alaska to New Zealand. The bird flies non-stop, without once breaking the journey to rest or eat. Then when spring comes, the bar-tailed godwit makes the 11,000-kilometre journey back to Alaska...

Professor of Ecology Anders Hedenström from Lund University has pondered over how this species of bird can fly so far without stopping. The distance is twice as far as previously known non-stop distances for migratory birds.

Professor Hedenström emphasises that the bar-tailed godwit is far superior to all aircraft constructed by humans when it comes to the art of flying for a long time without a break. The long-distance flight record for aircraft is held by QiniteQ's Zephyr, an unmanned solar-powered craft. It can remain in the air for 82 hours, around three and a half days, compared with the bar-tailed godwit's eight-day flight.

But what is it that makes the bar-tailed godwit able to fly 11 000 kilometres without a single break? How can these birds manage without sleep or food for eight whole days? One explanation is that they consume unusually little energy compared with other species of bird. Anders Hedenström has calculated that the bar-tailed godwit consumes 0.41 per cent of its body weight each hour during its long flight.
And this from a subsequent report:
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.


  1. Really neat! Though the longest time flight information is a bit dated...


    There are also 30+ scheduled commercial flights that are longer in distance:


    Still an amazing feat for a bird!

  2. Why New Zealand? Why not fly overland to Chile or some such? Who teaches them the way? Where is Dr Dolittle when you need him?

  3. Yes, Colin, you may be correct about all those longer aeroplane flights, but.... If you compare the size of the godwit to one of those commercial jets, then relatively speaking the bird wins many times hands down.

    As for the reason why they do this amazing feat, I heard once that some of these migratory birds have evolved from other migratory species many many millions of years and in that time the continents have moved considerably. But the newer birds haven't noticed the increased distances from A to B - well, who would? - and don't have the brains to question the flying distance anyway. So they just do it, as their parents did and their parents before them, although perhaps their name could be changed to Notawit or Havenowit... Wiki tells us that the name comes from the Old English for "good" and "white".

  4. For them to use that little energy they they would have to do a great deal more gliding than flying. Human glider pilots can traverse upwards of 2,600 km without any opportunity to flap their wings. Very impressive for the little birds, but not impossible.


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