merganser

Merganser is the common name for a group of small to medium-sized diving ducks that feed primarily on fish. They belong to the genus Mergus and related genera, and are collectively known as mergansers or sawbills because of their long, narrow bills with sharp, comb-like serrations used to grip slippery prey. Most species are found in temperate regions of Europe, Asia, and North America, with some inhabiting coastal and inland freshwater habitats.

Key species include the common merganser (Mergus merganser) and the red-breasted merganser (Mergus serrator) in the genus Mergus, as well as the hooded merganser (Lophodytes cucullatus), which is often treated in a separate genus. The scaly-sided merganser (Mergus squamatus) exists in parts of Asia and is considered endangered in some areas. Mergansers are typically slender with relatively long necks and pointed bills. Males often display striking plumage during the breeding season, while females are more camouflaged with brownish tones.

Behavior and ecology: mergansers are adept divers and hunt underwater for fish, their preferred prey, though they will also take aquatic invertebrates. They nest in cavities, typically laying a clutch incubated by the female while the male remains nearby. After hatching, the young are led to water by the female. These ducks migrate seasonally in many regions and face pressures from habitat loss, pollution, and climate change, though several species maintain stable populations.