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Factors Associated with Duck Nest Success
in the Prairie Pothole Region of Canada

Components of Mallard Production

Data were available for 49 of the 56 half-area-years studied during 1983-85. The west half of the Yorkton Study Area in 1985 was omitted because pairs were counted on only part of the area; the 6 others were excluded because no hatched nests were found on them. Correlations between log(Hatched Nests) and the 4 variables on the right-hand side of equation (4) were as follows:
log(Wetlands)                               
        r = 0.27 (P = 0.06),  

log(Pairs/Wetland)                          
        r = 0.13 (P = 0.38),  

log(Nests/Pair)                             
        r = 0.37 (P = 0.01),  

log(Hatched nests/Nest)                     
        r = 0.57 (P = 0.0001).
Thus, of these 4 variables, the one that most closely correlated with the number of hatched nests was the nest success rate, followed by a measure of the nesting effort, and then by the number of wet wetlands. The density of mallard pairs per wetland was not significantly correlated with Hatched Nests.

If the alternate model described by equation (5) is fitted, correlations between log(Hatched Nests) and the constituent variables are as follows:

log(Pairs)                                 
       r = 0.47 (P = 0.0007),

log(Nests/Pair)                            
       r = 0.37 (P = 0.01),  

log(Hatched nests/Nest)                    
       r = 0.57 (P = 0.0001).
In this formulation, the nest success rate is still the most influential, but is followed closely by the number of pairs, and then by the measure of nesting effort.
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