Natures wonders: gulls change wing shape (Introduction)

by David Turell @, Wednesday, January 02, 2019, 18:19 (262 days ago) @ David Turell

Helps them glide and fly i n different ways:

"Although a gliding bird's ability to stabilize its flight path is as critical as its ability to produce lift, relatively few quantitative studies on avian flight stability have been completed. This is what brought UBC researchers Christina Harvey, Vikram Baliga and Professor Doug Altshuler to Lavoie's wind tunnel lab at the University of Toronto Institute for Aerospace Studies (UTIAS).

"The researchers measured the lift and drag on 12 different wing shapes, all with slightly different elbow and shoulder angles. They determined that with a simple adjustment of a gull's elbow joints—either to expand its wings outwards or inwards—gulls are able to transition across a broad range of wing shapes to stabilize glide. When soaring, the wings are fully extended and have a more rounded shape, which increases their stability. When taking off or landing they are tucked in more and have a flatter shape.

"'If you can change the shape of the wings, you can create more stable configurations with lower drag when you want more endurance," says Lavoie. "Gulls can use updrafts to increase altitude so they don't have to flap their wings as much to conserve energy. But if they need to make quick maneuvers, like diving to catch fish, they can change the shape of the wing for that particular purpose.'"

Comment: It is not known if the original gulls had this ability from the beginning or developed it over time. If it wasn't present in the beginning they had trouble hunting over the oceans so one can wonder how they survived until they developed these adaptations of elbow joints which require exact design.

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