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Proceedings of the Royal Society B: Biological Sciences logoLink to Proceedings of the Royal Society B: Biological Sciences
. 1998 Mar 7;265(1394):409–414. doi: 10.1098/rspb.1998.0309

Sexual selection and tail streamers in the barn swallow

A P M ller, A Barbosa, J J Cuervo, F de Lope, S Merino, N Saino
PMCID: PMC1688894

Abstract

The functional significance of elongated, narrow tips of the tail feathers of certain birds, so-called tail streamers, has recently been discussed from an aerodynamic point of view, and the effects of sexual selection on such traits have been questioned. We review our long-term field studies using observational and experimental approaches to investigate natural and sexual selection in the barn swallow, Hirundo rustica, which has sexually size-dimorphic outermost tail feathers. Experimental manipulation of the length of the outermost tail feathers has demonstrated sexual selection advantages of tail elongation and disadvantages of tail shortening, with opposite effects for natural selection in terms of foraging efficiency, haematocrit and survival. These findings are contrary to the prediction of a general deterioration from both shortening and elongation, if the tail trait was determined solely by its effects on aerodynamic efficiency and flight manoeuvrability. Patterns of sexual selection in manipulated birds conform with patterns in unmanipulated birds, and selection differentials for different components of sexual selection in manipulated birds are strongly positively correlated with differentials in unmanipulated birds. Age and sex differences in tail length, and geographical patterns of sexual size dimorphism, are also consistent with sexual selection theory, but inconsistent with a purely natural selection advantage of long outermost tail feathers in male barn swallows.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Carpenter F. L. Bird hematocrits: effects of high altitude and strength of flight. Comp Biochem Physiol A Comp Physiol. 1975 Feb 1;50(2):415–417. doi: 10.1016/0300-9629(75)90035-3. [DOI] [PubMed] [Google Scholar]
  2. MØller AP, Nielsen JT. Differential predation cost of a secondary sexual character: sparrowhawk predation on barn swallows. Anim Behav. 1997 Dec;54(6):1545–1551. doi: 10.1006/anbe.1997.9998. [DOI] [PubMed] [Google Scholar]
  3. Møller A. P. Male ornament size as a reliable cue to enhanced offspring viability in the barn swallow. Proc Natl Acad Sci U S A. 1994 Jul 19;91(15):6929–6932. doi: 10.1073/pnas.91.15.6929. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. doi: 10.1098/rspb.1997.0030. [DOI] [PMC free article] [Google Scholar]
  5. Saino N., Bolzern A. M., Møller A. P. Immunocompetence, ornamentation, and viability of male barn swallows (Hirundo rustica). Proc Natl Acad Sci U S A. 1997 Jan 21;94(2):549–552. doi: 10.1073/pnas.94.2.549. [DOI] [PMC free article] [PubMed] [Google Scholar]

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