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 | ||
| 1964 | ||
| 1965 | ||
| 1966 | ||
| 1967 | ||
| 1968 | ||
| 1969 | ||
| 1970 | ||
| 1971 | ||
| 1972 | ||
| 1973 |
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
