Fig. 5. Wing angles (see Fig. 3)
through five wingbeats of a left turn. (A) Wing elevation angle (
) and
(B) sweep angle (
) measured at the wrist. (C) Elevation and (D) sweep
angle measured at the tip. Both the wrist and tip angles contained
rightleft asymmetries throughout the wingbeat sequence. Asymmetries in
position were most prominent at the stroke transitions and were much reduced
by mid-stroke. Measurements made at the wrist typically encompassed a smaller
range than measurements made at the tip because wrist flexion allows the tip
continues to move ahead and below the bird near the end of downstroke while
the wrist slows or even reverses direction.