A Study on the Bumps at the Leading Edge of the Wing Used by Hovering Birds

Inland birds make use of hovering to seize a prey from high above. At this time, they need to make accurate positioning control in order to focus on the target. The exact method of birds’ positioning control is: they let in the flow to the end of the wing, generate revolving power to the flow, and discharge it outside to have the effect of not being pushed back. At this time, the bumps which make accurate control are located at the entrance of the leading edge where the flow comes in playing the role of a valve which adjusts the amount of flow coming into the camber. With this technique, inland birds can execute hovering accurately.