Size and habitat composition of female mallard home ranges in the prairie-parkland region of Canada

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Abstract
Wetland density is believed to be an important determinant of variation in size of mallard (Anas platyrhynchos) home ranges, but hypothesized effects of upland habitat and female size and age have not been adequately evaluated. Thus, we investigated correlates of home-range size using unique radio-tracking data for 131 female mallards studied on 12 Canadian prairie-parkland sites in 1995–1998. Home-range size and habitat composition varied within and among study areas; overall, variation in home-range size was best modeled to include effects of seasonal and semipermanent wetlands (β = –0.06 ± 0.01; mean ± SE) and woodland–shrubland habitat (β = –0.03 ± 0.01). Contrary to predictions, we obtained no support for a positive association between home-range size and female body size or a negative relationship between home-range size and female age. After controlling for confounding effects of wetland density, home ranges were larger, on average, on study areas with lower densities of mallard breeding pairs; therefore, we suspect that individual home ranges were smaller in areas of high pair density because of increased intraspecific competition for breeding space. A higher proportion of woodland–shrubland habitat likely contributed to the smaller size of individual home ranges because of a greater relative availability of preferred nesting habitat.
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