Austin, J. E., Afton, A. D., Anderson, M. G., Clark, R. G., Custer, C. M., Lawrence, J. S., Pollard, J. B., and Ringelman, J. K., 2000, Declining scaup populations: issues, hypotheses, and research needs: Wildlife Society Bulletin, v. 28, no. 1, p. 254-263. Abstract Keywords Aythya affinis, Aythya marila, Management, Population, Research needs, Trends