Jamaica Bay Studies IV: Factors Affecting Distribution of Greater Scaup Aythya marila in a Coastal Estuary in New York, USA

Abstract

Greater scaup A. marila migrate through Jamaica Bay Wildlife Refuge on the east coast of North America and small numbers overwinter there. The 3600 ha refuge contains 2 man-made freshwater ponds and an extensive tidal bay. Scaup arrived on the refuge in late Sept. and were present until May, although peak numbers of birds were present from Oct.-Dec., and in March and April. Scaup concentrated on the tidal bay on falling and low tides and used the ponds on rising tides. Scaup concentrated on the bay during low temperatures and on the ponds during higher temperatures. Wind velocity affected scaup mainly in influencing flock size; scaup formed larger, denser flocks at high velocities. Multiple regression procedures indicated that date (only on the ponds), tidal factors, wind velocity and temperature were significant variables contributing to the variability in the number of scaup on the 3 census areas.