Birds Canada

The International Black Duck Adaptive Harvest Management Strategy Is Based, in Part, on Estimates of Black Duck Productivity as Measured by Adjusted Fall Age Ratios. Adjusted Fall Age Ratios Are Calculated Using Pre-season Banding Records, Hunter Reported Recoveries of Banded Birds, and Parts Collection Information. It Is Hypothesized That Black Duck Pre-season Banding Operations May Not Adequately Represent the Black Duck Breeding Population Due to the Locations and Timing of Banding Operations. It Is Posited That Birds Nesting in the Northern Part of Eastern Canada May Migrate Later Than Birds That Nest in Southern Canada and or Over-fly Southern Canada Making Them Unavailable for Banding. If Northern Nesting Birds Have Different Productivity Than Southern Nesting Birds Estimates of Productivity May Be Biased. This Project Will Use Stable Isotope Analysis of American Black Ducks Harvested in Southern Canada and the United States to Determine If the Origin of the Birds Is Similar Between the Two Samples. If the Samples Indicate Similar Origins the Hypothesis of Bias Will Be Discounted, If the Samples Are Different It May Indicate a Potential Bias and Need for Further Research.