Flight Mechanics and Control of Escape Manoeuvres in Hummingbirds. II. Aerodynamic Force Production, Flight Control and Performance Limitations

Authors

Bo Cheng, The Pennsylvania State University
Bret W. Tobalske, University of Montana, Missoula
Donald R. Powers, George Fox UniversityFollow
Tyson L. Hedrick, University of North Carolina at Chapel Hill
Yi Wang, Purdue University
Susan M. Wethington, Hummingbird Monitoring Network
George T.C. Chiu, Purdue University
Xinyan Deng, Purdue University

Document Type

Article

Publication Date

2016

Abstract

The superior manoeuvrability of hummingbirds emerges from complex interactions of specialized neural and physiological processes with the unique flight dynamics of flapping wings. Escape manoeuvring is an ecologically relevant, natural behaviour of hummingbirds, from which we can gain understanding into the functional limits of vertebrate locomotor capacity. Here, we extend our kinematic analysis of escape manoeuvres from a companion paper to assess two potential limiting factors of the manoeuvring performance of hummingbirds: (1) muscle mechanical power output and (2) delays in the neural sensing and control system. We focused on the magnificent hummingbird (Eugenes fulgens, 7.8 g) and the black-chinned hummingbird (Archilochus alexandri, 3.1 g), which represent large and small species, respectively. We first estimated the aerodynamic forces, moments and the mechanical power of escape manoeuvres using measured wing kinematics. Comparing active-manoeuvring and passive-damping aerodynamic moments, we found that pitch dynamics were lightly damped and dominated by the effect of inertia, while roll dynamics were highly damped. To achieve observed closed-loop performance, pitch manoeuvres required faster sensorimotor transduction, as hummingbirds can only tolerate half the delay allowed in roll manoeuvres. Accordingly, our results suggested that pitch control may require a more sophisticated control strategy, such as those based on prediction. For the magnificent hummingbird, we estimated that escape manoeuvres required muscle mass-specific power 4.5 times that during hovering. Therefore, in addition to the limitation imposed by sensorimotor delays, muscle power could also limit the performance of escape manoeuvres.

Comments

Originally published to Journal of Experimental Biology (2016) 219, 3532-3543 doi:10.1242/jeb.137570

Recommended Citation

Cheng, Bo; Tobalske, Bret W.; Powers, Donald R.; Hedrick, Tyson L.; Wang, Yi; Wethington, Susan M.; Chiu, George T.C.; and Deng, Xinyan, "Flight Mechanics and Control of Escape Manoeuvres in Hummingbirds. II. Aerodynamic Force Production, Flight Control and Performance Limitations" (2016). Faculty Publications - Department of Biological & Molecular Science. 104.
https://digitalcommons.georgefox.edu/bio_fac/104