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Aerodynamic flight performance in flap-gliding birds and bats
Florian T Muijres1, Per Henningsson, Melanie Stuiver
1Department of Biology, Lund University, Ecology Building, 223 62 Lund, Sweden. fmuijres@uw.edu
Journal of Theoretical Biology
|June 26, 2012
Summary
Birds and bats differ in flap-gliding flight economy. Flap-gliding saves birds energy, but not bats, due to distinct flight styles and morphology. This study models flap-gliding energetic costs.
Area of Science:
- * **Bioenergetics and Biomechanics:** Investigating the energetic efficiency of avian and chiropteran flight dynamics.
Background:
- * Flap-gliding, alternating flapping and gliding, is common in medium-to-large birds, reducing energetic costs compared to continuous flapping.
- * This flight mode is rarely observed in bats, suggesting potential differences in its applicability or efficiency.
Purpose of the Study:
- * To develop and apply a novel model for estimating the energetic economy of flap-gliding flight in animals.
- * To compare the energetic benefits of flap-gliding in a typical avian flap-glider (common swift) versus a non-flap-gliding bat (lesser long-nosed bat).
Main Methods:
- * Developed a model to estimate flap-gliding lift-to-drag ratio using empirical data from continuous flapping and gliding flights.
- * Applied the model to flight performance data of the common swift (Apus apus) and the lesser long-nosed bat (Leptonycteris yerbabuenae).
Main Results:
- * The common swift, a flap-glider, demonstrated up to 15% energy savings compared to continuous flapping, attributed to a high glide-to-flap lift-to-drag ratio.
- * The lesser long-nosed bat, not a natural flap-glider, showed no energetic cost reduction through this flight mode.
- * Differences in morphology, flight style, and wake dynamics explain the varied energetic outcomes between the swift and the bat.
Conclusions:
- * The developed model is a valuable tool for assessing flap-gliding energetic economy.
- * Flap-gliding is an energetically superior flight mode for species like the common swift that naturally employ it.
- * The lesser long-nosed bat's inability to benefit from flap-gliding highlights species-specific adaptations in flight mechanics.
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