Ecology of parasitism of brown-headed cowbirds by haematozoa

P. J. Weatherhead, G. F. Bennett

Research output: Contribution to journalArticlepeer-review


Sampled Molothrus ater over three summers in E Ontario, to use the cowbird-haematozoa system to assess practical and theoretical aspects of testing Hamilton and Zuk's parasite hypothesis of sexual selection. Most individuals resampled within and between years were consistently scored as parasitized or unparasitized, although some individuals changed status. Many hatching-year birds were parasitized. Significant variation within and between years in general parasite prevalence, specific parasite prevalence, and intensity of infections indicated that population estimates of parasitism would be highly dependent on when birds were sampled and on the age and sex composition of the sample. Parasitism did not have a negative effect on the health of cowbirds. Parasitized birds were also recaptured at the same rate as unparasitized birds between years. Results suggest a number of pitfalls, some potentially critical,to using haematozoa infections in passerines to test the Hamilton-Zuk hypothesis. -from Authors

Original languageEnglish (US)
Pages (from-to)1-7
Number of pages7
JournalCanadian journal of zoology
Issue number1
StatePublished - 1992
Externally publishedYes

ASJC Scopus subject areas

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


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