Saturday, April 23, 2011

Amazing' bird flies 11,000 km Nonstop' Without food or rest

London: How is it possible to fly 11,000 km without a single break? The bar-tailed godwit does it by consuming only 0.41 percent of its body weight each hour during its eight-day-long flight.

Every autumn, the bar-tailed godwit undertakes the 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 bird makes the 11,000 km journey back to Alaska.

Professor of Ecology Anders Hedenström from the Lund University, Sweden 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. 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, according to a statement of the Lund University.

The long-distance flight record for aircraft is held by the QinetiQ Zephyr, an unmanned solar-powered craft. It can remain airborne for 82 hours, around three-and-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 km without pausing to stop? 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 birds. Anders Hedenström has calculated that the bar-tailed godwit consumes 0.41 percent of its body weight each hour during its long flight. “This figure is extremely low compared with other migratory birds,” he says. However, other factors also play a role. It is important to have the right ratio of body weight to size to be able to carry sufficient energy for the entire flight.

The energy mainly comprises body fat, and to some extent also protein. It is also important to have an aerodynamic body shape so that air resistance is minimised. A further success factor is flight speed. The bar-tailed godwit is a quick flyer, which means that it can cover long distances in a reasonable time.

A comparison can be made with a completely different group of long-distance travellers from the animal kingdom - eels. To complete the bar-tailed godwit’s 11,000 km journey would take the eel 345 days, according to Hedenstrom.Source