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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