Male red-winged blackbirds distrust unreliable and sexually attractive neighbours

Robert Olendorf, Thomas Getty, Kim Scribner, Scott K. Robinson

Research output: Contribution to journalArticle

44 Scopus citations

Abstract

In many species, territorial neighbours fight to establish their mutual border and then develop a truce, known as the dear-enemy phenomenon, characterized by reduced vigilance and aggression along the border. We present evidence that among male red-winged blackbirds (Agelaius phoeniceus) the dear-enemy relationship is a form of reciprocal conditional cooperation that is stabilized, at least in part, by retaliation against cheaters. Simulated intrusions by randomly chosen neighbours were punished by a targeted increase in vigilance and aggression that persists for days. We interpret this increase in vigilance towards trespassers as a manifestation of distrust. The conditional decrease in vigilance and aggression is tempered by each neighbour's probability of cuckolding the focal male. Male red-winged blackbirds maintained greater vigilance and aggression towards sexually attractive neighbours that were more successful at extra-pair fertilizations (EPFs). It is unlikely that males directly observed neighbours copulating with their mates. They were more likely to assess a neighbour's ability to achieve extra-pair copulations using surrogate cues that correlate with success at EPFs, including body size. Our results suggest that red-winged blackbirds use rules that incorporate their neighbour's behaviour and quality in their territorial interactions with one another. Our results expand our understanding of cooperation for animals and for humans as well.

Original languageEnglish (US)
Pages (from-to)1033-1038
Number of pages6
JournalProceedings of the Royal Society B: Biological Sciences
Volume271
Issue number1543
DOIs
Publication statusPublished - May 22 2004

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All Science Journal Classification (ASJC) codes

  • Biochemistry, Genetics and Molecular Biology(all)
  • Immunology and Microbiology(all)
  • Environmental Science(all)
  • Agricultural and Biological Sciences(all)

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