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Full-Text Articles in Life Sciences
Effects Of Flight Speed Upon Muscle Activity In Hummingbirds, Bret W. Tobalske, Andrew A. Biewener, Douglas R. Warrick, Tyson L. Hedrick, Donald R. Powers
Effects Of Flight Speed Upon Muscle Activity In Hummingbirds, Bret W. Tobalske, Andrew A. Biewener, Douglas R. Warrick, Tyson L. Hedrick, Donald R. Powers
Faculty Publications - Department of Biological & Molecular Science
Hummingbirds have the smallest body size and highest wingbeat frequencies of all flying vertebrates, so they represent one endpoint for evaluating the effects of body size on sustained muscle function and flight performance. Other bird species vary neuromuscular recruitment and contractile behavior to accomplish flight over a wide range of speeds, typically exhibiting a Ushaped curve with maxima at the slowest and fastest flight speeds. To test whether the high wingbeat frequencies and aerodynamically active upstroke of hummingbirds lead to different patterns, we flew rufous hummingbirds (Selasphorus rufus, 3g body mass, 42Hz wingbeat frequency) in a variable-speed wind tunnel (0–10ms–1). …
Three-Dimensional Kinematics Of Hummingbird Flight, Bret W. Tobalske, Douglas R. Warrick, Christopher J. Clark, Donald R. Powers, Tyson L. Hendrick, Gabriel A. Hyder, Andrew A. Biewener
Three-Dimensional Kinematics Of Hummingbird Flight, Bret W. Tobalske, Douglas R. Warrick, Christopher J. Clark, Donald R. Powers, Tyson L. Hendrick, Gabriel A. Hyder, Andrew A. Biewener
Faculty Publications - Department of Biological & Molecular Science
Hummingbirds are specialized for hovering flight, and substantial research has explored this behavior. Forward flight is also important to hummingbirds, but the manner in which they perform forward flight is not well documented. Previous research suggests that hummingbirds increase flight velocity by simultaneously tilting their body angle and stroke-plane angle of the wings, without varying wingbeat frequency and upstroke: downstroke span ratio. We hypothesized that other wing kinematics besides stroke-plane angle would vary in hummingbirds. To test this, we used synchronized highspeed (500·Hz) video cameras and measured the threedimensional wing and body kinematics of rufous hummingbirds (Selasphorus rufus, 3·g, N=5) …
Take-Off Mechanics In Hummingbirds (Trochilidae), Bret W. Tobalske, Douglas L. Altshuler, Donald R. Powers
Take-Off Mechanics In Hummingbirds (Trochilidae), Bret W. Tobalske, Douglas L. Altshuler, Donald R. Powers
Faculty Publications - Department of Biological & Molecular Science
Initiating flight is challenging, and considerable effort has focused on understanding the energetics and aerodynamics of take-off for both machines and animals. For animal flight, the available evidence suggests that birds maximize their initial flight velocity using leg thrust rather than wing flapping. The smallest birds, hummingbirds (Order Apodiformes), are unique in their ability to perform sustained hovering but have proportionally small hindlimbs that could hinder generation of high leg thrust. Understanding the take-off flight of hummingbirds can provide novel insight into the take-off mechanics that will be required for micro-air vehicles. During take-off by hummingbirds, we measured hindlimb forces …