File Download

There are no files associated with this item.

  Links for fulltext
     (May Require Subscription)
Supplementary

Article: The effect of tail streamer length on aerodynamic performance in the barn swallow

TitleThe effect of tail streamer length on aerodynamic performance in the barn swallow
Authors
KeywordsBarn swallows
Flight performance
Norberg mechanism
Natural selection
Maneuverability
Hirundo rustica
Sexual selection
Issue Date2000
Citation
Behavioral Ecology, 2000, v. 11, n. 2, p. 228-238 How to Cite?
AbstractThe elongated tail of the male barn swallow (Hirundo rustica) is regarded as one of the classic examples of a male trait exaggerated by female choice. However, recently a hypothesis has been proposed suggesting that the streamers, or elongated outer tail feathers, may aid aerodynamic performance through the Norberg mechanism, providing lift at slow speeds and high angles of attack when the tail is fully spread. The possibility exists that the tail streamer has evolved under natural selection, sexual selection, or a combination of both selection pressures. We tested these three hypotheses by reducing the streamer length of free-flying swallows and measuring their aerodynamic performance, using stereo-video. Measurements of flight performance were made from the digitized three-dimensional flight paths. Five flight variables best described the individual variation in flight performance. Four of these five parameters - mean velocity, mean curvature, maximum agility, and mean rate change of curvature in the XY plane - had significant second-order polynomial relationships with tail streamer manipulation. The first and second principal components (from principal components analysis of the flight variables) also showed similar relationships with streamer manipulation. The combination of a curvilinear relationship between flight performance and streamer length and an aerodynamic optimum between 0 and 20 mm reduction is only predicted if both natural and sexual selection have been acting on streamer morphology. Our data therefore suggest that sexual selection has extended streamer length by around 10 mm beyond its aerodynamic optimum. We suggest that both natural and sexual selection have been important in shaping tail morphology in the barn swallow, and the relative importance of both selection pressures is discussed.
Persistent Identifierhttp://hdl.handle.net/10722/230704
ISSN
2015 Impact Factor: 3.029
2015 SCImago Journal Rankings: 1.698

 

DC FieldValueLanguage
dc.contributor.authorBuchanan, Katherine L.-
dc.contributor.authorEvans, Matthew R.-
dc.date.accessioned2016-09-01T06:06:35Z-
dc.date.available2016-09-01T06:06:35Z-
dc.date.issued2000-
dc.identifier.citationBehavioral Ecology, 2000, v. 11, n. 2, p. 228-238-
dc.identifier.issn1045-2249-
dc.identifier.urihttp://hdl.handle.net/10722/230704-
dc.description.abstractThe elongated tail of the male barn swallow (Hirundo rustica) is regarded as one of the classic examples of a male trait exaggerated by female choice. However, recently a hypothesis has been proposed suggesting that the streamers, or elongated outer tail feathers, may aid aerodynamic performance through the Norberg mechanism, providing lift at slow speeds and high angles of attack when the tail is fully spread. The possibility exists that the tail streamer has evolved under natural selection, sexual selection, or a combination of both selection pressures. We tested these three hypotheses by reducing the streamer length of free-flying swallows and measuring their aerodynamic performance, using stereo-video. Measurements of flight performance were made from the digitized three-dimensional flight paths. Five flight variables best described the individual variation in flight performance. Four of these five parameters - mean velocity, mean curvature, maximum agility, and mean rate change of curvature in the XY plane - had significant second-order polynomial relationships with tail streamer manipulation. The first and second principal components (from principal components analysis of the flight variables) also showed similar relationships with streamer manipulation. The combination of a curvilinear relationship between flight performance and streamer length and an aerodynamic optimum between 0 and 20 mm reduction is only predicted if both natural and sexual selection have been acting on streamer morphology. Our data therefore suggest that sexual selection has extended streamer length by around 10 mm beyond its aerodynamic optimum. We suggest that both natural and sexual selection have been important in shaping tail morphology in the barn swallow, and the relative importance of both selection pressures is discussed.-
dc.languageeng-
dc.relation.ispartofBehavioral Ecology-
dc.subjectBarn swallows-
dc.subjectFlight performance-
dc.subjectNorberg mechanism-
dc.subjectNatural selection-
dc.subjectManeuverability-
dc.subjectHirundo rustica-
dc.subjectSexual selection-
dc.titleThe effect of tail streamer length on aerodynamic performance in the barn swallow-
dc.typeArticle-
dc.description.natureLink_to_subscribed_fulltext-
dc.identifier.scopuseid_2-s2.0-0034090562-
dc.identifier.volume11-
dc.identifier.issue2-
dc.identifier.spage228-
dc.identifier.epage238-

Export via OAI-PMH Interface in XML Formats


OR


Export to Other Non-XML Formats