Why Are Scaup Declining? Workshop
Participants Seek Answers
byJane Austin
U.S. Geological Survey
Article taken from Waterfowl 2000
North American populations of greater and lesser scaup began to decline in the early 1980s. Unlike most other duck species, scaup populations have not responded to recent improvements in water conditions on the breeding grounds. The 1998 May waterfowl survey indicated 3.5 million breeding scaup, representing a 16% decline from 1997 and the lowest numbers since surveys began in 1955. The North American Waterfowl Management Plan's goal for breeding scaup is 6.3 million.
Concerns about declining scaup populations have led to increasing interest and research efforts. To facilitate research, the U.S. Geological Survey's Northern Prairie Wildlife Research Center and Ducks Unlimited Canada sponsored a workshop at the Research Center from September 9 through 10, 1998. Forty biologists from the U.S. Fish and Wildlife Service, Canadian Wildlife Service, U.S. Geological Survey, Ducks Unlimited Canada, flyways, states, and academic organizations attended. They shared information and discussed research needs and opportunities to collaborate or coordinate activities.
Workshop participants reviewed and discussed the most recent data concerning population status and distribution, breeding biology, contaminants, survival, and hunting. They targeted four key areas for detailed discussion: (1) changes in the western boreal forest and possible impacts on reproductive success; (2) impacts of contaminants and nutrient acquisition patterns on reproductive success; (3) population dynamics and survival of scaup, including the role of hunting; and (4) information needed to manage greater and lesser scaup as separate species.
Presentations provided information that offered insights into the current status of scaup populations. Recent analyses indicate that most breeding population declines are occurring in the western boreal forests of Canada. Breeding populations are stable or increasing in Alaskan boreal forests, tundra, and prairie-parkland areas. Banding data provide some insights into the survival and movements of scaup among breeding, migration, and wintering areas, but few data are available after 1979.
Although nest success is usually relatively high, there is little information on duckling survival, and boreal forest data are limited to a few areas. Contaminant levels in scaup wintering in the Great Lakes and some coastal areas are high and may be negatively affecting reproductive success. Important food resources are affected by contaminants and changing environmental conditions. All discussions noted a common need for information on affiliations of breeding scaup with migration and wintering grounds.
Recommended research and information needs included:
- more detailed analyses of existing breeding and wintering survey data;
- delineation of the distribution of greater lesser scaup;
- additional studies of breeding biology in both boreal forests and parkland regions;
- broad-scale monitoring of sex ratios, pairs, and broods;
- evaluation of the impacts of fire, logging, and climate change in boreal forests;
- assessment of contaminants in eggs and breeding females;
- improved survival estimates from mark/resighting studies and banding; and
- investigation of nutrient dynamics, food habits, and habitat use during spring migration.
This workshop is the first step in focusing research directions and stimulating communication and partnerships among diverse groups concerned with scaup conservation and management. Biologists throughout the United States and Canada will be working together to examine existing data in greater detail and to develop research efforts to fill critical information needs. A synthesis report from the workshop will be completed this winter.
For more information, contact Jane Austin, U.S. Geological Survey, Biological Resources Division, Northern Prairie Wildlife Research Center, 8711 37th Street S.E., Jamestown, North Dakota 58401, or call (701) 253-5510, or fax (701) 253-5553, or e-mail jane_austin@usgs.gov.
