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

Table 11: Estimated Red Fox Predation Rates on Mallards

Table 11. Estimated red fox predation rates on mallards.

				Predation rate^b
Year	Average number of mallards at surface of den	Expansion factor^a	Percentage female	Male	Female
1969	0.35	16.17	76.8	1.313	4.347
1970	0.36	16.17	81.0	1.106	4.715
1971	0.22	16.17	76.9	0.822	2.736
1972	0.26	16.17	74.3	1.080	3.124
1973	0.22	16.17	86.7	0.473	3.084
Average	0.28	16.17	79.1	0.959	3.601
Standard deviation				0.323	0.872
				(r = 0.657)

^a Expansion factor = 2 x (1/0.47) x 3.8--see pages 9-10 for explanation.
^b Per fox family

Previous Section-- Table 10: Sex Ratios of Adult Mallards Found at Red Fox Dens
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Next Section-- Table 12: Annual Survival and Recovery Rates for Adult Mallards