The Mississippi Flyway midwinter population survey (MWS) indicates that American black ducks (Anas rubripes) have been rapidly declining for the last 10 years. We found a negative relationship between MWS and Ontario (Canada) midwinter counts for black ducks. Thus, as number of black ducks in the MWS decreased, Ontario midwinter counts increased. A shift in midwinter distribution of black ducks may be partly responsible for the decreasing trend in MWS counts. We recommend that midwinter black duck surveys be expanded to more sites in southern Canada and northeastern United States that currently are not sampled to better assess winter habitat use and improve the midwinter black-duck population index.
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1 January 2009
Evidence for Black Duck Winter Distribution Change
Rodney W. Brook,
R. Kenyon Ross,
Kenneth F. Abraham,
David L. Fronczak,
J. Chris Davies
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Journal of Wildlife Management
Vol. 73 • No. 1
January 2009
Vol. 73 • No. 1
January 2009
abundance
Anas rubripes
black duck
distribution
midwinter survey
range shift
