Incredibly, the birds spent only one percent of their time in the air flapping their wings, mostly during takeoff. A bird has flown more than five hours, traveling more than 160 kilometers, without flapping its wings.
“Condors are expert pilots – but we just didn’t expect them to be that expert,” said study co-author and biologist Emily Shepard, University of Swansea, Wales.
The results were published Monday in the journal Proceedings of the National Academy of Sciences.
“The conclusion that they hardly ever flap their wings and fly away 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 features – gusts of wind, warm and rising air currents and air currents pushed up by soil characteristics such as mountains.
Learning to ride drafts allows some birds to travel long distances while minimizing the effort of flapping their wings.
Scientists who study flying animals generally consider two types of flight: flying and gliding. The difference can be compared to pedaling an uphill bike, compared to coasting 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 storks and ospreys catch 17% and 25% of their migratory land flights, respectively.
The extreme ability of the Andean condor to glide is essential to its treasured lifestyle, which requires hours a day to bypass the high mountains in search of a carrion meal, said co-author and biologist Sergio Lambertucci from the study at the National University of Comahue in Argentina.
“When you see condors going around in circles, they take advantage of these thermal heaves,” or bursts of hot air, he said.
The recording devices were programmed to drop birds after about a week.
Getting them back was not that easy.
“Sometimes the devices fell into nests on huge cliffs in the middle of the Andes mountains, and we needed three days just to get there,” said Lambertucci.