Scaling of Takeoff Mechanics in Doves (Columbidae)

TOBALSKE, B.W.*; BIEWENER, A.A.; ZIMMERMAN, B.B.: Scaling of Takeoff Mechanics in Doves (Columbidae)

Takeoff ability is considered to be of central importance to the ecology and evolution of animal flight, yet few studies have examined the magnitude and timing of ground reaction forces during takeoff in flying birds. Predictions of takeoff ability suggest that: 1) peak accelerations during maximum takeoff should scale negatively with increasing body mass and 2) initial air velocity is independent of body mass. To test these predictions, we studied takeoff mechanics in three species of doves (Columbidae) that varied in body mass from 40 to 492 g. The birds initiated flight while standing on a force plate that enabled measurement of vertical and horizontal ground reaction forces. After takeoff, the birds ascended nearly vertically and landed on a perch 2 m above the force plate. Force recordings were sampled at 500 Hz; simultaneous high-speed video (250 Hz) was obtained for analysis of wing and body kinematics. Among the three species, the legs contributed proportionally more than the wings to flight velocity at the start of the second downstroke. Peak acceleration decreased proportional to the -0.08 power of body mass while takeoff velocity scaled proportional to mass to the 0.11 power. These results support prediction 1 but not prediction 2. Similar scaling patterns are reported for jump performance in terrestrial animals. Average takeoff speed among dove species ranged from 2.0 to 2.7 m/s, which highlights that at no point during takeoff were the wings used at 0 m/s, the speed at which the power cost for flapping flight is highest. (NSF IBN 9923699)

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