Morphological Aspects of Avian Tail Movements: A Functional Approach in Hirundines

Publication Type:	Journal Article
Year of Publication:	1996
Authors:	Moreno, E, MØLLER, ANDERSPAPE
Journal:	The Auk
Volume:	113
Issue:	3
Date Published:	1996
ISBN Number:	00048038
Keywords:	Delichon, Delichon urbica, Delichon urbicum, Hirundinidae, Hirundo, Hirundo rustica, Riparia, Riparia riparia
Abstract:	It has been proposed that the aerodynamically optimal tail shape in birds should be triangular when spread and forked when closed. According to this aerodynamic model, any area distal to the point of maximum width contributes drag, which is proportional to total tail area, but not lift. One assumption of this model seems to be uniformity in structures responsible for tail movements (i.e. tail muscles) among species. We tested for different muscular arrangements in species with different tail shapes. By dissecting tail muscles in three hirundine species (Barn Swallow [Hirundo rustica], Common House-Martin [Delichon urbica], and Bank Swallow [Riparia riparia]), we demonstrate anatomical differences associated with deeply forked tails and speculate that such differences compensate for the increased cost of longer feathers. Therefore, we propose that reliable assessment of the aerodynamic cost of tails should be based on tail shape as well as internal anatomical structures such as muscles.
URL:	http://www.jstor.org/stable/4088985
Short Title:	The Auk

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