Life Sciences Commons^™

The Allometry Of Daily Energy Expenditure In Hummingbirds: An Energy Budget Approach, Anushu Shankar, Donald R. Powers, Liliana M. Dávalos, Catherine H. Graham

Faculty Publications - Department of Biological & Molecular Science

1. Within-clade allometric relationships represent standard laws of scaling between energy and size, and their outliers provide new avenues for physiological and ecological research. According to the metabolic-level boundaries hypothesis, metabolic rates as a function of mass are expected to scale closer to 0.67 when driven by surface-related processes (e.g. heat or water flux), while volume-related processes (e.g. activity) generate slopes closer to one.

2. In birds, daily energy expenditure (DEE) scales with body mass (M) in the relationship log (DEE)=2.35+0.68×log (M), consistent with surface-level processes driving the relationship. However, taxon-specific patterns differ from the scaling slope of all birds. …

Integrating Morphology And Kinematics In The Scaling Of Hummingbird Hovering Metabolic Rate And Efficiency, Derrick J. E. Groom, M. Cecilia B. Toledo, Donald R. Powers, Bret W. Tobalske, Kenneth C. Welch Jr.

Faculty Publications - Department of Biological & Molecular Science

Wing kinematics and morphology are influential upon the aerodynamics of flight. However, there is a lack of studies linking these variables to metabolic costs, particularly in the context of morphological adaptation to body size. Furthermore, the conversion efficiency from chemical energy into movement by the muscles (mechanochemical efficiency) scales with mass in terrestrial quadrupeds, but this scaling relationship has not been demonstrated within flying vertebrates. Positive scaling of efficiency with body size may reduce the metabolic costs of flight for relatively larger species. Here, we assembled a dataset of morphological, kinematic, and metabolic data on hovering hummingbirds to explore the …

Flight Mechanics And Control Of Escape Manoeuvres In Hummingbirds. Ii. Aerodynamic Force Production, Flight Control And Performance Limitations, Bo Cheng, Bret W. Tobalske, Donald R. Powers, Tyson L. Hedrick, Yi Wang, Susan M. Wethington, George T.C. Chiu, Xinyan Deng

Faculty Publications - Department of Biological & Molecular Science

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 …