Fig.3. (A,B) Wingbeat amplitude (wrist amplitude, filled circles; wingtip amplitude, open squares) increased with air speed (wrist amplitude; GLM; bird 1: F_1,9=276.05, P<0.0001, r²=96.5%; bird 2: F_1,8=241.85, P<0.0001, r²=96.4%). The duration of the downstroke (C,D) decreased, and the downstroke angular velocity (E,F) increased with air speeds exceeding 7ms^-1. A,C,E, bird 1; B,D,F, bird 2. Values are means ± S.E.M. N=4 at air speeds 11 and 13ms^-1 (bird 2, D,F); all other N=5 flight sequences.

Return to article