Abstracts

Presented by Jake Chronister - Email: Chronisterjake@gmail.com

Historically, tens of thousands of greater scaup (Aythya marila) wintered at Great South Bay, Long Island, New York but this population declined to near zero by the early 1990s. Since super-storm Sandy in 2012, numbers of wintering scaup increased substantially and were at historic levels in 2018 and 2019. It is hypothesized that super-storm Sandy flushed Great South Bay of legacy organic matter and pollutants, revitalizing sand substrates and traditional foods of molluscivorous ducks (e.g., duck clams [Gemma gemma]). Because of the return of scaup to Great South Bay, we established a scaup banding station there, February – April 2019, to determine the feasibility of trapping and banding 1,000s of scaup per winter. Our aim was to help meet continental banding goals for scaup and facilitate winter population estimates using mark-recapture methodology. We captured 1,141 scaup (925 lesser [Aythya affinis] and 216 greater scaup) over four weeks at two traps sites; and 161 and 17 were recaptures of lesser and greater scaup, respectively. We will present results of mark-recapture analyses to estimate populations of lesser and greater scaup and determine factors affecting capture probabilities at Great South Bay.