The eagle has landed

New Scientist reports: [edited]

Jumbo jets do it, pterosaurs used to do it - and now we know that eagles do it too. As they come in to land, planes, prehistoric reptiles and steppe eagles deploy a flap on the front edge of the wing.

Using a high-speed video camera, Anna Carruthers and her colleagues from the University of Oxford filmed a male steppe eagle as it touched down on its handler's arm. The 500-frames-per-second camera caught the wing-flap movement as a feathery "travelling wave" that spread from the wrist of the wing to the shoulder. Previous footage had been too slow to catch this movement.

Carruthers says that the wave appears to be initiated automatically when aerodynamic conditions change as the bird slows down to land, probably to act as a stabiliser or to maintain lift at low speed. She says the finding could help develop bird-sized surveillance aircraft known as micro air vehicles.

"The potential of the high-speed camera approach is enormous," says Matthew Wilkinson, an animal flight researcher at the University of Cambridge. "It's given us an unprecedented insight into the workings of an eagle wing." Other large birds are also thought to use front-edge wing flaps.
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