Date of Award

Spring 4-11-2018

Semester of Degree


Document Type

Open Access Thesis

Degree Name

M.S. in Environmental and Forest Biology


Environmental and Forest Biology

Major Professor

Jonathan Cohen


Michael Schummer

Steering Committee Member

Bryan Swift

Steering Committee Member

Brian Underwood


Mallards and American black ducks are closely related species with little niche separation. I sought to identify management actions to promote the Finger Lakes population of wintering black ducks in the face of competition with mallards. Occupancy by black ducks of points on lake shorelines was negatively influenced by building presence. Local black duck colonization varied negatively with proportion of developed land and local black duck extinction varied positively with dock density. Based on GPS tracking, mallards used agriculture and developed habitats more than black ducks. Black ducks selected emergent wetlands to a greater degree than available within their home range. I did not statistically detect behavioral differences between species although proportion time spent foraging when in forested wetlands was eight times greater for black ducks than mallards. Black duck conservation in wintering areas should focus on restoring agricultural areas to emergent marsh and maintaining shoreline areas with limited development.