Estimating habitat carrying capacity for American black ducks wintering in southern New Jersey

Graduate Research Assistants: Dane Cramer (M.S. Wildlife Ecology)

Collaborators: Paul Castelli (New Jersey Division of Fish and WIlldife), Tina Yerkes (Ducks Unlimited), Black Duck Joint Venture, Ducks Unlimited, New Jersey Division of Fish and WIlldife, Forsythe and Cape May National Wildlife Refuges, New Jersey Waterfowlers

As coastal habitat availability has declined throughout the Atlantic flyway, the American black duck (Anas rubripes) has suffered population declines. My research attempts to build an all inclusive model for estimating wintering carrying capacity through estimates of 1) habitat use, 2) time-energy budgets, 3) food resource utilization, and 4) landscape level food availability along southern coastal New Jersey. To do so, I will be doing radio telemetry to examine habitat use, instantaneous scan samples to quantify time spent in behavioral states, and examining food availability and consumption through hunter harvested crop collections and invertebrate and moist soil seed habitat sampling. By filling in all of the puzzle pieces of a simple supply and demand model, this research will provide an estimate of the amount and type(s) of habitat required to support and maintain projected population. In terms of management implications, coupling our estimate of carrying capacity with Mid-winter inventory data should allow managers to determine whether current populations are below, at, or above that level and adjust management practices accordingly.

Photo credit: Dane Cramer