Discrimination of vocal performance by male swamp sparrows

Adrienne L. DuBois, Stephen Nowicki, William A. Searcy

Research output: Contribution to journalArticlepeer-review

42 Scopus citations


In aggressive communication, the interests of signalers and receivers are directly opposed, presenting a challenge to the maintenance of reliable signaling. Index signals, whose production is constrained by physical ability, offer one solution to the reliable signaling problem. Vocal performance, the ability to produce physically challenging songs, is likely such a signal in swamp sparrows. Maximum vocal performance varies between males and is correlated with aspects of quality. However, vocal performance can be modulated in aggressive contexts by increasing the frequency bandwidth and trill rate of songs. This study examines receiver response to (1) differences in performance of the same song types by different signalers and (2) individual modulation of performance between contexts. Results demonstrate that male receivers show differential response to between-male differences in song type performance, but do not show differential response to the smaller scale modulations of performance produced by individuals singing the same song type at different times. This pattern suggests that vocal performance cannot be effectively cheated and may therefore serve as a good example of an index signal.

Original languageEnglish (US)
Pages (from-to)717-726
Number of pages10
JournalBehavioral Ecology and Sociobiology
Issue number4
StatePublished - Apr 2011


  • Aggression
  • Birdsong
  • Communication
  • Reliable signaling
  • Vocal performance

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Animal Science and Zoology


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