Linking Lesser Scaup Population Decline To The Environment:Issues Of Time, Space And Scale

Continental breeding populations of Lesser scaup(Aythya affinis)have been declining since the 1980's. The most comprehensive explanation for this is the Spring Condition Hypothesis (SCH),which predicts that female lesser scaup are arriving on breeding/nesting areas in poorer condition than they did historically, possibly due to lack of sufficient forage along spring migration routes. Diet analyses of lesser scaup have shown aquatic macroinvertebrates to be their primary food, inferring that prey availability is a key factor influencing body condition and reproductive success, however, factors affecting macro invertebrate abundance in the prairie pothole region (PPR)and their relationship to lesser scaup are not well known. Although lesser scaup surveys span several years, lack of long-term macroinvertebrate data raises critical questions about linking their population decline to changes in macroinvertebrate abundance. The aim of this study is to test the viability of the SCH by collating literature from previous and current research, combining field data, microcosms and remote sensing to investigate both the causes as well as the mechanisms behind of the problem and to use this as the basis for predicting long term trends and possible remediation.