Please use this identifier to cite or link to this item:
Appears in Collections:Biological and Environmental Sciences Journal Articles
Peer Review Status: Refereed
Title: Assessing the aerodynamic effects of tail elongations in the house martin (Delichon urbica): Implications for the initial selection pressures in hirundines
Author(s): Park, Kirsty
Evans, Matthew
Buchanan, Katherine Louise
Keywords: Flight performance
Tail streamers
sexual selection
Natural selection
Birds Anatomy
Birds Behavior
Sexual selection in animals
Issue Date: Oct-2000
Date Deposited: 5-Mar-2008
Citation: Park K, Evans M & Buchanan KL (2000) Assessing the aerodynamic effects of tail elongations in the house martin (Delichon urbica): Implications for the initial selection pressures in hirundines. Behavioral Ecology and Sociobiology, 48 (5), pp. 364-372.
Abstract: Of the three species of Hirundine that breed sympatrically across the U.K., one, the barn swallow, has outer tail feathers elongated into streamers, whereas the other two species, the house martin and the sand martin, do not. The tail streamer of the barn swallow is regarded as a classic example of a sexually selected trait. Recent evidence, however, has suggested that streamers may have evolved largely through natural selection for enhanced flight performance and increased maneuverability. We tested the hypotheses that small streamers 1) increase performance in turning flight, but 2) decrease performance in flight variables related to velocity. We manipulated the lengths of house martin outer tail feathers and measured changes in their free-flight performance, using stereo-video to reconstruct the birds’ 3D flight paths. Five flight variables were found to best describe individual variation in flight performance. Of these five, the three variables determining maneuverability predicted that flight performance would be optimized by a 6 to 10mm increase in the length of the outer tail feathers. In contrast, for mean velocity and mean acceleration, extension of the outer tail feathers appears to have a detrimental effect on flight performance. We suggest that the initial selection pressure for streamers in ancestral short-tailed ‘barn swallows’ was via natural selection for increased maneuverability. In addition, we propose that the benefits of increased maneuverability has differed between hirundines in the past, such that the cost of increasing the length of the outer tail feather has, to date, outweighed the benefits of doing so in streamer-less hirundines.
DOI Link: 10.1007/s002650000250
Rights: The original publication is available at

Files in This Item:
File Description SizeFormat 
park2000b.pdfFulltext - Accepted Version176.74 kBAdobe PDFView/Open

This item is protected by original copyright

Items in the Repository are protected by copyright, with all rights reserved, unless otherwise indicated.

The metadata of the records in the Repository are available under the CC0 public domain dedication: No Rights Reserved

If you believe that any material held in STORRE infringes copyright, please contact providing details and we will remove the Work from public display in STORRE and investigate your claim.