In the high, arid mountains of Patagonia, an Andean condor managed to travel more than 100 miles without flapping its wings once. This five-hour ultramarathon flight was recorded during a new study of the massive scavenger’s hyper-efficient flight, reports Christina Larson for the Associated Press.
All that efficiency is in the service of keeping all 33 pounds of the world’s heaviest soaring bird aloft. The researchers found that the massive scavengers use their ten-foot wingspans to strategically surf currents of rising air called thermals to reduce costly flapping to the bare minimum. Tiny sensors attached to eight condors revealed that across more than 250 hours in the air the birds spent just one-percent of their flight time flapping.
The study, published this week in the journal the Proceedings of the National Academy of Sciences, also found that getting airborne in the first place accounted for a full three-quarters of the condors’ flapping, reports BBC News. The condors in the study spent around three hours a day in the air searching the Andes and their foothills for carcasses to feed on, according to the paper.
“Condors are expert pilots—but we just hadn’t expected they would be quite so expert,” Emily Shepard, a biologist at Swansea University and co-author of the study, tells the AP.
Also speaking with the AP, David Lentink, a bird flight expert at Stanford University who was not involved in the research, comments that “the finding that they basically almost never beat their wings and just soar is mind-blowing.”
The researchers had been hoping to figure out if there were various weather patterns or types of terrain that forced these soaring machines to resort to beating their huge wings. “Surprisingly, the amount they flapped hardly changed whether they were in the Andes or the steppe, or whether it was windy or not,” writes Shepherd in the Conversation.
The most challenging moments for the condors occurred when they were trying to glide between weaker thermals that Shepherd speculates might have taken them close to the ground.
In a statement, study co-author Sergio Lambertucci, a conservation ecologist at the National University of Comahue in Argentina, explains: “This is a critical time as birds need to find rising air to avoid an unplanned landing.” He likens the behavior of thermals to lava lamps, “with bubbles of air rising intermittently from the ground when the air is warm enough. Birds may therefore arrive in the right place for a thermal, but at the wrong time.”
Collecting the data that went into the study took the researchers five years, including many hours of waiting around by sheep carcasses to tag the condors and then grueling expeditions to physically collect the tags once they fell off. Retrieving the tags was necessary because they recorded too much data to transmit via satellite or cellular networks, the researchers write in the Conversation.
The difficulty of accessing the remote and often dangerously steep locations in the high Andes favored by adult condors actually caused the researchers to modify their study. To save time and increase the odds of successfully retrieving the fallen tags, the researchers started targeting immature condors, which tend to roost in groups in the more accessible rolling hills of the Patagonian steppe, according to the Conversation.
This change means that the impressive feats of aerial efficiency recorded in the study were all the work of relatively novice fliers in condor-terms. Captive Andean condors have reached ages of up to 75 years old, and aren’t considered mature until they’re at least five years old but sometimes not until they reach the ripe old age of 11.
In the Conversation, Shepherd notes that if these South American maestros of the wind get better at exploiting thermals as they age, it’s possible the wizened adults might be able to soar greater distances with even fewer flaps.