Red-breasted Merganser

The red-breasted merganser (Mergus serrator) is a species of duck known for its slender, serrated bill and elegant body shape, making it adept at diving and catching fish. Adult males are distinguished by their dark green to almost black heads, white neck ring, and reddish-brown breast, which contrast sharply with their dark upperparts and white underparts. Females and juveniles are less colorful, featuring grayish bodies with brown heads. The red-breasted merganser measures 52-58 cm (20.5-22.8 in) in length with a wingspan of 70-86 cm (27.5-33.8 in). It is among the fastest flying ducks, capable of reaching speeds up to 128 km/h. This species can be confused with the common merganser (Mergus merganser), where the male lacks the red breast and is a lot more white and the female has a white patch on its chin.

Red-breasted mergansers are primarily found in coastal marine environments during the winter but breed along rivers and lakes in northern forest regions across North America, Europe, and Asia. They are highly adapted to aquatic life, diving skillfully to catch fish, their main diet. These birds also consume crustaceans, insects, and small amphibians. Their habitat choice is influenced by the availability of clear water, which is crucial for their foraging efficiency .

This species exhibits a clear pattern of migration, generally breeding in the northern parts of its range and wintering along the coasts. The migration timings are quite punctual, with birds moving to breeding grounds in early spring and returning to winter habitats as temperatures begin to drop in late autumn .

Breeding starts in late April to May, depending on the latitude. Red-breasted mergansers are ground-nesters, often choosing sites near water hidden among vegetation. The female lays 8-12 eggs which she incubates alone for about 30 days. The ducklings are precocial and take to water shortly after hatching, although they remain under maternal care and protection for several weeks until they fledge at about 60-70 days old .

The red-breasted merganser is currently classified as least concern on the IUCN Red List, indicating stable global populations. However, local declines due to habitat degradation, oil spills, and entanglement in fishing gear have been noted. Conservation efforts are focused on habitat preservation and monitoring of population trends to prevent significant declines.