Dispersal, dominance behaviour, and body reserves in mallards during winter : mechanisms involved and implications for the individual / Richard Pattenden.
Material type:
TextSeries: Thesis. (M.Sc.)Publication details: Edmonton, AB : University of Alberta, 1988.Description: x, 108 p. : ill. ; 28 cmOnline resources: Abstract: Reasons for a biased sex ratio in isolated populations of wild mallards (Anas platyrhynchos) wintering at a northern latitude (53 degrees 35'N),were investigated. As well, dominance behaviour and effects of body reserves on the well being of the individual and its subsequent reproductive performance were examined using a flock of captive yearling mallards. A sex ratio biased towards males existed at the onset of winter during both years of study, but during one environmentally harsh winter the proportion of females in the population, as well as the size of the latter, continued to decline over winter. Differential dispersal at the onset of winter was probably the major factor creating biased sex ratios in most northern wintering duck populations, a bias that apparently can be exacerbated by adverse environmental conditions. Among captive mallards, males dominated females and paired birds dominated singles. Dominance status of an individual, established during early life, was not rela
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Electronic Report
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Electronic Library | Non-fiction | PAT (Browse shelf(Opens below)) | Available | 1556 |
Includes bibliographical references.
Reasons for a biased sex ratio in isolated populations of wild mallards (Anas platyrhynchos) wintering at a northern latitude (53 degrees 35'N),were investigated. As well, dominance behaviour and effects of body reserves on the well being of the individual and its subsequent reproductive performance were examined using a flock of captive yearling mallards. A sex ratio biased towards males existed at the onset of winter during both years of study, but during one environmentally harsh winter the proportion of females in the population, as well as the size of the latter, continued to decline over winter. Differential dispersal at the onset of winter was probably the major factor creating biased sex ratios in most northern wintering duck populations, a bias that apparently can be exacerbated by adverse environmental conditions. Among captive mallards, males dominated females and paired birds dominated singles. Dominance status of an individual, established during early life, was not rela