Filters: Types: OGC WMS Layer (X) > Types: Citation (X) > partyWithName: Afton, Alan D. (X)

Filters Date Range Past year (0) Past month (0) Past week (0) Past day (0) Custom range... To   Search Extensions Citation (3) Shapefile (3) Types Downloadable (3) Map Service (3) OGC WFS Layer (3) Shapefile (3) Contacts Anderson, Michael G. Anteau, Michael J. Arnold, Todd W. Austin, Jane E. Clark, Robert G. More... Categories Data (3) Publication (3) View Results as: JSON ATOM CSV

Declining Scaup Populations: A Retrospective Analysis of Long-Term Population and Harvest Survey Data We examined long-term databases concerning population status of scaup (lesser [Aythya affinis] and greater scaup [A. marila] combined) and harvest statistics of lesser scaup to identify factors potentially limiting population growth. Specifically, we explored evidence for and against the general hypotheses that scaup populations have declined in association with declining recruitment and/or female survival. We examined geographic heterogeneity in scaup demographic patterns that could yield evidence about potential limiting factors. Several biases exist in survey methodology used to estimate scaup populations and harvest statistics; however, none of these biases likely accounted for our major findings that (1) the... Categories: Data, Publication; Types: Citation, Downloadable, Map Service, OGC WFS Layer, OGC WMS Layer, Shapefile; Tags: Baseline 5-Data, Lesser Scaup, Species of Concern: Birds Declining Scaup Populations: Issues, Hypotheses, and Research Needs The population estimate for greater (Aythya marila) and lesser (Aythya affinis) scaup (combined) has declined dramatically since the early 1980s to record lows in 1998. The 1998 estimate of 3.47 million scaup is far below the goal of 6.3 million set in the North American Waterfowl Management Plan (NAWMP), causing concern among biologists and hunters. We summarize issues of concern, hypotheses for factors contributing to the population decline, and research and management needs recommended by participants of the Scaup Workshop, held in September 1999. We believe that contaminants, lower female survival, and reduced recruitment due to changes in food resources or breeding-ground habitats are primary factors contributing... Categories: Data, Publication; Types: Citation, Downloadable, Map Service, OGC WFS Layer, OGC WMS Layer, Shapefile; Tags: Birds, Monitoring 1-Changes in Plant and Animal Distribution: Fauna Temporal variation in survival and recovery rates of lesser scaup Categories: Data, Publication; Types: Citation, Downloadable, Map Service, OGC WFS Layer, OGC WMS Layer, Shapefile; Tags: Baseline 5-Baseline data, species of concern: Lesser scaup