Mergus is the genus of the typical mergansers, fish-eating ducks. The Hooded Merganser is not of this genus but closely related.
Although they are seaducks, most of the mergansers prefer riverine habitats, with only the Red-breasted Merganser being common at sea. These large fish-eaters have serrated edges to their bills to help them grip their prey. Along with the Smew and Hooded Merganser, they are therefore often known as "sawbills".
