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Distribution and Abundance of Predators that Affect
Duck Production: Prairie Pothole Region


Table 3. P-values and odds rations from Mantel-Haenzel tests (Fleiss 1973) of inter- and intraspecific relations of nest spacing by avian predator species in study areas in the prairie pothole region, 1983-88.a,b

Species pair or species P-value
Nc Oddsd AssociationeHomogeneityf
American crow-great horned owl170.410.1930.950
Red-tailed hawk-great horned owl123.380.002<0.001
Swainson's hawk-great horned owl1800.252>0.999
American crow-red-tailed hawk190.350.0050.992
Swainson's hawk-red-tailed hawk110.750.7630.988
American crow-swainson's hawk201.350.260<0.001
American crow252.02<0.001<0.001
Swainson's hawk190.460.299>0.999
Red-tailed hawk180.120.002>0.999

aAssociation refers to an overall tendency to avoid or aggregate.
bHomogeneity indicates the consistency of the association across study area-years.
cNumber of study area-years.
dOdds < 1 indicates avoidance of nesting near each other; odds > 1 indicates aggregation of nests.
eP-value based on chi-squared distribution with 1 degree of freedom.
fP-value based on chi-squared distribution with N-1 degrees of freedom.

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