Vendredi 29 Novembre 2024
taille du texte
   
Mercredi, 25 Mai 2011 23:30

Chubby Little Birds Make Superfast Long-Distance Fights

Rate this item
(0 Votes)

Chubby Little Birds Make Superfast Long-Distance Fights

In the record-keeping annals of life on Earth, make way for the great snipe — a small, stocky shorebird that takes the fastest long-distance, nonstop flights of any animal that’s not in an airplane.

During its annual migration, a single snipe may fly for 96 consecutive hours, covering more than 4,000 miles. That’s four days without stopping or sleeping, sometimes at average speeds of 50 miles per hour.

“We know of no other animal that travels this rapidly over such a long distance,” wrote researchers led by biologist Raymond Klaasen of Sweden’s Lund University in a May 25 Biology Letters study.

‘An unexpected and previously unknown strategy in bird migration.’

In May of 2009, Klaasen and colleagues put geolocating tags on 10 great snipes captured on Sweden’s western coast. One year later, they recaptured three of the birds. Their tags contained the first detailed records ever of great-snipe migration.

The voyages proved to be extreme, even for the already-extreme world of avian migration. The birds had flown nonstop to central Africa in late August 2009. One trip spanned 2,800 miles, another 3,800 miles, and the third more than 4,200 miles. Respectively these took 48, 72 and 84 hours.

The longest known nonstop flight was made by a godwit that flew 7,145 miles from Alaska to New Zealand in nine days, but at an average speed of about 35 miles per hour. Klaasen’s great snipes topped out at 50 miles per hour.

Unlike godwits, however, which have no choice but to fly straight over the Pacific without landing, great snipes have many opportunities to stop and feed. Why they choose not to is unknown. They “represent an unexpected and previously unknown strategy in bird migration,” wrote Klaasen’s team.

Chubby Little Birds Make Superfast Long-Distance Fights

The flight records of three great snipes. At left is their autumn migration; at right, spring migration, which is interrupted by a breeding ground stopover in central Europe.  Biology Letters

Making the great snipes’ speed even more impressive, it was done without wind assistance. When the researchers cross-referenced the flight records with wind records from U.S. satellites, they found little evidence of tail winds. The birds manage on their own.

All this was accomplished despite the relatively non-aerodynamic shape of snipe wings, which lack the pointed tips characteristic of long-distance flight efficiency. Instead they seem to rely on massive stores of fat accumulated during autumn eating binges.

As described by one 19th-century hunter’s account cited by Klaasen’s team, “Great snipes are so fat and heavy in autumn that their skin sometimes ruptures when the shot bird hits the ground.”

Image: Charles Lam/Flickr.

See Also:

Citation: “Great flights by great snipes: long and fast non-stop migration over benign habitats.” Raymond H. G. Klaassen, Thomas Alerstam, Peter Carlsson, James W. Fox and Ake Lindstrom. Biology Letters, May 25, 2011.

Authors:

French (Fr)English (United Kingdom)

Parmi nos clients

mobileporn