The American black duck (Anas rubripes) is an outcome species for the

health of the Chesapeake Bay. In order to estimate the impact that changes in

black duck habitat will have on the Bay’s wintering population, the relationship

between black ducks and the species comprising their diets must be better

understood. This study was part of a larger effort to build a comprehensive

bioenergetics model for black ducks wintering in the Chesapeake Bay. Using

black ducks as model species, functional response curves were created for five

experimental species known to be consumed by black ducks. For each curve,

three regressions representing the three types of functional response models were

run. In examining the regression fits along with using biological inferences, the

functional response types for each experimental species were determined to be

type I for softstem bulrush seeds, type II for widgeon grass, horned pondweed,

and Eastern mosquitofish, and type III for saltmarsh snails. This research was

used to determine critical foraging densities and will contribute to the

bioenergetics model that will help identify areas where conservation efforts

should be targeted in order to benefit black ducks and contribute to the overall

health of the Chesapeake Bay.