Study sheds light on how efficiently the world’s largest flying bird rides air currents to stay airborne for hours without flapping its wings.
The Andean condor has a wingspan of 3 meters (10 feet) and weighs up to 15 kg (33 lb), making it the heaviest flying bird in the world.
For the first time, a team of scientists tied up the recording equipment that eight condors in Patagonia called “daily diaries” to record each heartbeat for more than 250 hours of flight.
Incredibly, the birds spent only 1% of their time in the air flapping their wings, mainly during takeoff. A bird flew more than five hours, covering more than 100 miles (160 km), without flapping its wings.
“Condors are expert pilots, but we didn’t expect them to be that expert,” said Professor Emily Shepard, co-author of the study and a biologist at the University of Swansea in Wales.
The results were published Monday in the journal Proceedings of the National Academy of Sciences.
“The finding that they basically hardly ever hit their wings and just shoot themselves is mind-boggling,” said David Lentink, a bird flight expert at Stanford University, who was not involved in the research.
For birds, the sky is not empty, but a landscape of invisible characteristics: gusts of wind, warm updrafts, and drafts pushed upward by ground features such as mountains.
Learning to handle drafts allows some to travel long distances while minimizing the effort of flapping their wings.
Scientists who study flying animals generally consider two types of flight: flapping flight and flight flight. The difference can be compared to selling a bike uphill off the coast downhill, said Bret Tobalske, a bird flight expert at the University of Montana, who was not involved in the study.
Previous studies have shown that white storks and ospreys flutter 17% and 25% of their migratory land flights, respectively.
The experience of the Andean condor to fly is essential to its scavenger lifestyle, which requires hours a day of traveling high mountains in search of a carrion meal, said Sergio Lambertucci, co-author of the study and a biologist at the National University of Comahue in Argentina .
“When you see condors circling, they are taking advantage of those thermal rises,” or gusts of hot air, he said.
The recording devices were programmed to fall off the birds after about a week.
Recovering them was not so easy. “Sometimes the devices fell into nests on huge cliffs in the middle of the Andes mountains, and we needed three days to get there,” said Lambertucci.
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