Experimental confirmation of the polygyny threshold model for red-winged blackbirds

S. Pribil, W. A. Searcy

Research output: Contribution to journalArticlepeer-review

34 Scopus citations


The polygyny threshold model assumes that polygynous mating is costly to females and proposes that females pay the cost of polygyny only when compensated by obtaining a superior territory or male. We present, to the authors' knowledge, the first experimental field test to demonstrate that females trade mating status against territory quality as proposed by this hypothesis. Previous work has shown that female red-winged blackbirds (Agelaius phoeniceus) in Ontario prefer settling with unmated males and that this preference is adaptive because polygynous mating status lowers female reproductive success. Other evidence suggests that nesting over water increases the reproductive success of female red-winged black-birds. Here we describe an experiment in which females were given choices between two adjacent territories, one owned by an unmated male without any over-water nesting sites and the other by an already-mated male with over-water sites. Females overwhelmingly preferred the already-mated males, demonstrating that superior territory quality can reverse preferences based on mating status and supporting the polygyny threshold model as the explanation for polygyny in this population.

Original languageEnglish (US)
Pages (from-to)1643-1646
Number of pages4
JournalProceedings of the Royal Society B: Biological Sciences
Issue number1476
StatePublished - Aug 7 2001


  • Agelaius
  • Mating systems
  • Polygyny
  • Polygyny threshold model

ASJC Scopus subject areas

  • Agricultural and Biological Sciences(all)
  • Agricultural and Biological Sciences (miscellaneous)


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