The mechanics and behavior of cliff swallows during tandem flights.

Autor:	Shelton RM; Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA., Jackson BE; Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA Biological and Environmental Sciences, Longwood University, Farmville, VA 23909, USA., Hedrick TL; Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA thedrick@bio.unc.edu.
Jazyk:	angličtina
Zdroj:	The Journal of experimental biology [J Exp Biol] 2014 Aug 01; Vol. 217 (Pt 15), pp. 2717-25. Date of Electronic Publication: 2014 May 22.
DOI:	10.1242/jeb.101329
Abstrakt:	Cliff swallows (Petrochelidon pyrrhonota) are highly maneuverable social birds that often forage and fly in large open spaces. Here we used multi-camera videography to measure the three-dimensional kinematics of their natural flight maneuvers in the field. Specifically, we collected data on tandem flights, defined as two birds maneuvering together. These data permit us to evaluate several hypotheses on the high-speed maneuvering flight performance of birds. We found that high-speed turns are roll-based, but that the magnitude of the centripetal force created in typical maneuvers varied only slightly with flight speed, typically reaching a peak of ~2 body weights. Turning maneuvers typically involved active flapping rather than gliding. In tandem flights the following bird copied the flight path and wingbeat frequency (~12.3 Hz) of the lead bird while maintaining position slightly above the leader. The lead bird turned in a direction away from the lateral position of the following bird 65% of the time on average. Tandem flights vary widely in instantaneous speed (1.0 to 15.6 m s(-1)) and duration (0.72 to 4.71 s), and no single tracking strategy appeared to explain the course taken by the following bird. (© 2014. Published by The Company of Biologists Ltd.)
Databáze:	MEDLINE
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