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Wildlife Monographs

Red Fox Predation on Breeding Ducks
in Midcontinent North America

Tables

Table 8. Fox predation rate indices (ducks/den from surface food remains only) for dabbling ducks in 2 physiographic regions comprising Barnes, Kidder, Stutsman counties, North Dakota, relative to May pond numbers and dabbling duck densities, 1969-73a.

Correlation withb
1969 1970 1971 1972 1973 Avg. CVc May ponds Population
Total dens 102 81 94 98 126        
May pond (x 103) 170 152 87 148 54        
All dabbling ducksd
Population (x 103) 878 666 629 651 423 649 24.9 0.867*  
Predation rate index
Drift plain 2.94 1.65 0.72 1.27 0.78 1.47 61.4    
Missouri Coteau 2.58 2.00 1.59 1.92 1.13 1.84 29.0    
Combined avg. 2.76 1.83 1.16 1.60 0.96 1.66 43.4 0.874* 0.930**
Mallard
Population (x 103) 114 129 111 94 103 110 11.9 0.305  
Predation rate index 0.33 0.36 0.22 0.30 0.22 0.29 22.3 0.912** 0.525
Northern pintail
Population (x 103) 195 145 81 145 61 125 43.2 0.971**  
Predation rate index 0.69 0.42 0.29 0.37 0.18 0.39 48.9 0.866* 0.945**
Northern shoveler
Population (x 103) 73 77 39 74 31 59 37.3 0.971***  
Predation rate index 0.35 0.21 0.09 0.11 0.05 0.16 74.4 0.810* 0.689
Blue-winged teal
Population (x 103) 333 174 284 199 149 227 34.0 0.406  
Predation rate index 0.65 0.28 0.29 0.33 0.19 0.35 50.1 0.712 0.832*
Gadwall
Population (x 103) 117 111 104 104 71 101 17.6 0.875*  
Predation rate index 0.20 0.19 0.14 0.26 0.14 0.19 26.8 0.759 0.486

aFrom USFWS Breeding Pair Surveys for Stratum 46.
bSignificance of correlation coefficients, 3 df: * = P < 0.10, ** = P < 0.05, and *** = P < 0.01.
cCoefficient of variation.
dRemains of 806 dabbling ducks identified from surface remains found at 501 dens, and includes all species listed plus American wigeon, green-winged teal, wood duck, and all unidentified dabbling ducks. Forty-four percent of the ducks and 49% of the dens were from the Drift Plain; the remainder were from the Missouri Coteau.

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