Written by Peter Pearsall/Photo by Dan Streiffert
The Common merganser (Mergus merganser), also known as the “goosander” in Europe, is a large, sleek diving duck with a long, narrow bill adapted for catching fish. The common merganser is one of four extant species in the genus Mergus.
Males have a white body with a dark green, iridescent head, a slender red bill, and black upperparts, while females have gray bodies with a chestnut-colored head and a distinctive white chin patch.
Common mergansers are native to North America, Europe, and northern Asia. In North America, they are widely distributed across Canada and the northern United States. They are migratory, often wintering in milder southern areas and along coastlines and large rivers. They prefer clear, freshwater lakes, rivers, and streams with plenty of fish, especially in forested or mountainous areas. In winter, they may be found in brackish or coastal waters if freshwater sources freeze over.
Common mergansers are primarily piscivorous: fish make up the bulk of their diet. They dive underwater to catch small to medium-sized fish, aided by serrated edges on their bills that firmly grip their slippery prey. They may also consume aquatic invertebrates, amphibians, and small mammals.
Breeding takes place in late spring, with females typically nesting in natural tree cavities or artificial nest boxes near water. They lay between 6–17 eggs, which the female incubates for around 28–35 days. The ducklings are precocial—they can feed themselves shortly after hatching—though they stay close to their mother for protection.
