The most massive flying birds of our time – Andean condors – have mastered an incredibly economical planning flight: they have to flap their wings almost exclusively for take-off.
The wingspan of Andean condors can reach three meters, and weight – 15 kilograms. These are the largest winged scavengers and the heaviest flying birds of our time. Their weight and size make very stringent requirements for energy efficiency and flight efficiency. And it seems condors have succeeded in this.
They are able to stay in the air for hours and overcome more than 150 kilometers, without ever flapping their wings. Sliding from one air stream to another, condors move almost always in the planning “mode”. Flapping flight takes only about 1.3 total time – this is what Emily Shepard and her colleagues from the British University of Swansea write in a new article published in PNAS.
During field experiments, which lasted from 2013 to 2018, scientists tracked the movements of eight Andean condors in Argentina, attaching miniature sensors to the birds that recorded each flap of the wings – and saved GPS tracks of their movements. In total, about 250 hours of recordings were collected, which showed that the condors resort to waving efforts almost exclusively at the time of take-off or for braking during landing.
Three-quarters of the total number of strokes accounted for take-off, but the birds spent most of their flight time motionless, looking for prey far below. The record was 172 kilometers and five hours, during which one condor did not make a single flap of its wings. For this, condors also use the weather: for the sake of maximum energy saving, most of the flights are made by them when it is cool and windy. Scientists believe that giant archeopteryxes and other flying lizards, which reached even larger sizes, could act in a similar way.