Realized Reproductive Success of Polygynous Red-Winged Blackbirds Revealed by DNA Markers Academic Article uri icon

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  • Hypervariable genetic markers, including a novel locus-specific marker detected by a mouse major histocompatibility complex probe, reveal that multiple paternity is common in families of polygynous red-winged blackbirds (Agelaius phoeniceus). Almost half of all nests contained at least one chick resulting from an extra-pair fertilization, usually by a neighboring male. Genetically based measures of reproductive success show that individual males realize more than 20% of their overall success from extra-pair fertilizations, on average, and that this form of mating behavior confounds traditional measures of male success. The importance of alternative reproductive tactics in a polygynous bird is quantified, and the results challenge previous explanations for the evolution of avian polygny.


  • Gibbs, HL
  • Weatherhead, PJ
  • Boag, PT
  • White, Bradley
  • Tabak, LM
  • Hoysak, DJ

publication date

  • December 7, 1990