Flight mechanics and control of escape manoeuvres in hummingbirds. I. Flight kinematics [RESEARCH ARTICLE]

Bo Cheng, Bret W. Tobalske, Donald R. Powers, Tyson L. Hedrick, Susan M. Wethington, George T. C. Chiu, and Xinyan Deng
Hummingbirds are nature's masters of aerobatic manoeuvres. Previous research shows that hummingbirds and insects converged evolutionarily upon similar aerodynamic mechanisms and kinematics in hovering. Herein, we use three-dimensional kinematic data to begin to test for similar convergence of kinematics used for escape flight and to explore the effects of body size upon manoeuvring. We studied four hummingbird species in North America including two large species (magnificent hummingbird, Eugenes fulgens, 7.8 g, and blue-throated hummingbird, Lampornis clemenciae, 8.0 g) and two smaller species (broad-billed hummingbird, Cynanthus latirostris, 3.4 g, and black-chinned hummingbirds Archilochus alexandri, 3.1 g). Starting from a steady hover, hummingbirds consistently manoeuvred away from perceived threats using a drastic escape response that featured body pitch and roll rotations coupled with a large linear acceleration. Hummingbirds changed their flapping frequency and wing trajectory in all three degrees of freedom on a stroke-by-stroke basis, likely causing rapid and significant alteration of the magnitude and direction of aerodynamic forces. Thus it appears that the flight control of hummingbirds does not obey the ‘helicopter model’ that is valid for similar escape manoeuvres in fruit flies. Except for broad-billed hummingb...

Source: Journal of Experimental Biology - November 15, 2016 Category: Biology Authors: Cheng, B., Tobalske, B. W., Powers, D. R., Hedrick, T. L., Wethington, S. M., Chiu, G. T. C., Deng, X. Tags: RESEARCH ARTICLE Source Type: research