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USGS · 5211120

Population trends of black ducks and mallards from the North American Breeding Bird Survey: Are increases in mallards associated with declines in black ducks?

J.R. Sauer·Sam Droege
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J.R. Sauer, Sam Droege. 1997. Population trends of black ducks and mallards from the North American Breeding Bird Survey: Are increases in mallards associated with declines in black ducks?. https://pubs.usgs.gov/publication/5211120

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