Greater Scaup, Aythya marila, Nest Site Characteristics on Grassy Island, New Brunswick

Abstract

We studied Greater Scaup (Aythya marilla) nest site selection on Grassy Island, New Brunswick, during 1995 and 1996 by describing site selection in relation to habitat characteristics and association with larids using univariate comparisons. We pooled nesting data from both years and found that nesting sites were significantly closer to larid colonies and the edge of the patch of vegetation in which the nests were situated, had less forb canopy cover, more sedge cover, greater overhead concealment and lateral cover at 0–0.25 m, and less ground moisture than random sites. We evaluated Greater Scaup nests delimited as close to or far from larid colonies at 30 m and documented that nests closer to larid colonies were found in shorter vegetation that was closer to the edge of the patch of vegetation with less lateral cover at 0.25–0.5 m, but had greater overhead concealment than nests farther away. Advancements in the ecological understanding of the species, including habitat use patterns and species associations, will increase the likelihood of conservation successes.