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Impact of Red Fox Predation on the Sex Ratio of Prairie Mallards

Table 5: Estimates of Mallard Spring Breeding Populations


Table 5. Estimates of mallard spring breeding populations (in thousands) for the reference area, 1963-73.
Year Number in strata 45 and 46a Number of males in reference areab
1963
474.8
211.3
1964
376.6
167.6
1965
356.3
158.6
1966
417.1
185.6
1967
412.4
183.5
1968
359.4
159.9
1969
355.9
158.4
1970
636.9
283.4
1971
684.5
304.6
1972
525.6
233.9
1973
449.0
199.8

a From May waterfowl survey of U.S. Fish and Wildllife Services, adjusted for visibility.
b Adjusted for size differential between strata 45 and 46 and our reference area.



Previous Section-- Table 4: Various Indices of Red Fox Densities and Estimated Spring Population of Red Fox Families
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Next Section-- Table 6: Incidence of Mallards Found Above Ground at Red Fox Rearing Dens

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