NPWRC :: Response of Nesting Ducks to Predator Exclosures and Water Conditions During Drought

GIF-A graph of 5 duck species breeding populations

Fig. 1. Breeding populations of 5 duck species, number of May ponds, and area of May ponds on study areas in North Dakota (Kulm, Jamestown) and Minnesota (Detroit Lakes), 1987-91.

GIF-A graph of regression ratio estimates of breeding pairs of 5 duck species

Fig. 2. Comparison of regression ratio estimates with land-area and water-area ratio estimates of breeding pairs of 5 duck species on study areas in North Dakota (Kulm, Jamestown) and Minnesota (Detroit Lakes), 1987-91. Each sample point represents an estimate for a species, study area, and year. Solid lines are expected results if estimators exhibit the same bias. Dashed lines were fit by simple linear regression.

GIF-Graphs showing changes in proportions of ducks within the exclosures

Fig. 3. Changes in proportion of ducks nesting within exclosures on study areas in North Dakota (Kulm, Jamestown) and Minnesota (Detroit Lakes), 1987-91.

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Response of Nesting Ducks to Predator Exclosures and Water Conditions During Drought

Figures