Mergus

Mergus is a genus of ducks in the family Anatidae, commonly known as mergansers. Members are medium to large ducks with long, slender bills that bear sharp serrations along the edges, a adaptation that helps them catch fish. They are primarily fish-eaters and are skilled divers, often foraging by pursuing prey underwater.

Distribution and habitat: The genus is native to the temperate and boreal regions of the Northern Hemisphere, including North America, Europe, and Asia. Mergansers typically inhabit freshwater lakes, rivers, and coastal waters, and many species winter in milder zones. They favor habitats that provide tree cavities or broken shorelines for nesting and roosting.

Description and behavior: In most species, males have striking head patterns, sometimes with iridescent coloration and a white or contrasting collar, while females are generally brownish with paler throats. Juveniles resemble females at first. Mergansers nest in tree cavities or crevices near water. They usually lay about 6–12 eggs, with incubation lasting several weeks. Both sexes participate in parental care, and fledging occurs after a few weeks of dependance on the parents. These ducks are often migratory, moving to more temperate regions during winter.

Taxonomy and species: The genus includes several species, such as the common merganser (Mergus merganser) and the red-breasted merganser (Mergus serrator). Taxonomic status of related taxa has changed in some classifications, with certain species formerly placed in Mergus moved to other genera. Conservation status varies by species and region, with habitat and prey availability influencing population trends.