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

Table 19: Apportionment of Mallard Remians Found at Red Fox Dens

Table 19. Apportionment of mallard remains found at red fox dens to fox predation and to accumulation of scavenged birds.
Case
Sex
Percent of birds found at dens killed by foxes
Predation rate per fox family
Accumulation rate per fox family
"Other" spring mortality ratea
Spring sex ratio
0
Male
100
0.96
0.0
0.0
126:100
Female
100
3.60
0.0
0.0
I
Male
50
0.48
0.48
2.52
118:100
Female
75
2.70
0.90
4.54
II
Male
50
0.48
0.48
2.52
117:100
Female
87
3.12
0.48
2.35

a Added to rate of "other" summer mortality.

Previous Section-- Table 18: Sex Composition of Adult Ducks Found at Mink Dens
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Next Section-- Table 20: Parameters of Distributions Used to Generate Random Variates

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