The Common Merganser is a large, cold-hardy, fish-eating duck that nests worldwide near large lakes and rivers in northern forested habitats. In North America, this species winters on large lakes, rivers, and reservoirs of the central United States and along the coasts. Also known as Goosander, a name sometimes restricted to Eurasian populations, the species has a variety of popular North American names that refer to mergansers in general, names such as sawbill, fish duck, and sheldrake. In flight, this duck has a flat, pointed profile. It generally nests in tree cavities (or nest boxes) but will nest on the ground or in crevices. Females breed in their second year, generally lay one clutch per year, and will lay their white eggs in the nests of other cavity-nesting ducks.
As a top predator in aquatic food chains, this species has served as an indicator of environmental health both for contaminants (pesticides, toxic metals) and lake acidification. Because this merganser was thought to threaten salmon and trout stocks, its diet has been intensively studied, and in some regions it has been the target of eradication programs. Although we lack a reliable estimate of its current population size, trend data suggest that the North American population is generally stable or increasing.
Help author an account about this species from a Neotropical perspective.