Factors Associated with Duck Nest Success
in the Prairie Pothole Region of Canada
Nest Success by Study Area
We derived independent estimates of DSR's by habitat class for each half-area-year and each of the 5 common species. We weighted the DSR's of nests in each habitat class and half-area-year by the estimated proportion of nests initiated in that habitat class and half-area-year; weighted DSR's were pooled and averaged across all habitat classes to estimate the DSR for the entire area-year. Before weighting and pooling, we tested for differences in DSR's by habitat class between halves of each area-year using linear contrasts (Snedecor and Cochran 1980). We used pooled estimates by habitat class for halves where DSR's did not differ (P > 0.10). We detected significant differences in DSR's by habitat class between east and west halves of Yorkton (1985), Ceylon (1983, 1984) Hanley (1982,1985), Leask (1985), Denzil (1985), and Holden (1983) study areas. The 0.10 level of significance was chosen for this analysis because we believed that nest success by area-year would be affected less by treating the halves as being different, when they were in fact similar, than by treating them as being similar, when they were actually different.
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