Hooded Merganser (Lophodytes cucullatus)
The hooded merganser is a commonly encountered cavity-nesting waterfowl species that breeds along the Tittabawassee River and can often be seen foraging along the river. Our research aimed to determine the potential exposure of the hooded merganser populations residing within the Tittabawassee River floodplain to site-specific contaminants, in particular, dioxins and furans.
Hooded mergansers were chosen as a representative species of the aquatic food web because they forage primarily on fish. Hooded mergansers are obligate cavity-nesters (i.e., they don’t excavate their own cavities and are dependent on natural cavities or, for this study, artificial nest boxes), and have a restricted foraging range while nesting. Hooded mergansers are located near the top of the aquatic food web.
Contaminant concentrations in the tissues of hooded mergansers were analyzed to determine their exposure to site-specific compounds. For the hooded merganser, collected tissues included fresh and addled eggs.
Productivity data collected on hooded merganser populations were limited mostly to box occupancy and clutch size.
Hooded merganser data have been collected from reference areas in Sanford, Michigan, and the Pine and Chippewa rivers in and around the Chippewa Nature Center, and study areas downstream of Midland, Michigan, ranging to the Shiawassee National Wildlife Refuge.
Integrating the findings from these studies provided us with the information necessary to estimate the exposure of hooded mergansers residing within the Tittabawassee River floodplain to site-specific contaminants.