Distribution and Abundance of Predators that Affect
Duck Production: Prairie Pothole Region
Tables
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 | Associatione | Homogeneityf | ||
| Interspecific | |||||
| American crow-great horned owl | 17 | 0.41 | 0.193 | 0.950 | |
| Red-tailed hawk-great horned owl | 12 | 3.38 | 0.002 | <0.001 | |
| Swainson's hawk-great horned owl | 18 | 0 | 0.252 | >0.999 | |
| American crow-red-tailed hawk | 19 | 0.35 | 0.005 | 0.992 | |
| Swainson's hawk-red-tailed hawk | 11 | 0.75 | 0.763 | 0.988 | |
| American crow-swainson's hawk | 20 | 1.35 | 0.260 | <0.001 | |
| Intraspecific | |||||
| American crow | 25 | 2.02 | <0.001 | <0.001 | |
| Swainson's hawk | 19 | 0.46 | 0.299 | >0.999 | |
| Red-tailed hawk | 18 | 0.12 | 0.002 | >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.
