What is a Red-Breasted Merganser?

The Red-Breasted Merganser is a medium-sized duck that can be found throughout the Northern Hemisphere. They may be identified by their red, serrated bills, the spiky crests on their heads and rust-colored breasts. Closely related to the other Merganser species, the Red-Breasted Merganser belongs to the subfamily of Merginae, or seaducks. Like many of its Merganser relatives, it summers in high, Northern latitudes such as Alaska, Northern Canada, Europe and Asia. During winter months it migrates South and tends to inhabit coastlines and saltwater estuaries. The Red-Breaster Merganser is a diving duck that can use its long, serrated bill to feed primarily on fish.

Like the other Mergansers, the Red-Breasted Merganser is a migratory duck that tends to breed in high, Northern latitudes. Unlike the other Mergansers, it tends to prefer marine environments when summering in lower latitudes. It can summer in riverine environments as well, such as lakes, rivers and streams, though this is less common. Another thing that tends to set the Red-Breasted Merganser apart from other ducks is that they can mate comparatively late in the season. Their young tend to not even fledge until early Fall, and have developed protections against the cold, Northern waters.

Adult Red-Breasted Mergansers are sexually dichromatic, meaning males and females have different coloring. Females have rust-colored heads and breasts, grey bodies and white undersides. Males can be colored similarly to females, though their plumage may change dramatically during mating season. The mating plumage of an adult male can include an iridescent green head, white neck and a chest that is darker red and speckled with black. Both genders have similar spiky crests and white spots under their wings that are visible only during flight. Juveniles tend to be similar in coloring to females.

The Red-Breasted Merganser is considered a diving duck and has a long, thin body and a serrated bill. Its body shape can help to facilitate diving, while the serrated bill can be used to grasp fish. This serrated bill has led to it being known as a "saw-bill" duck. This nickname is also shared with ducks such as the other Mergansers and the Smew. Bill serration is typically observed in duck species that feed primarily on fish. Ducks that feed on mollusks and other food sources will tend more toward the stereotypical smooth bill. Red-Breasted Mergansers, however, may also take prey such as insects, frogs and mollusks to supplement their diet.

The Red-Breasted Merganser (Mergus serrator) is a distinctive diving duck known for its slender, serrated bill and striking plumage. Males have a dark green head, a white neck ring, and a reddish-brown breast, while females sport a rusty head with a shaggy crest. They inhabit freshwater lakes and coastal waters, diving to catch fish, their primary diet.

Red-Breasted Mergansers are found across North America, Europe, and Asia. They breed in the northern regions near freshwater lakes and rivers, and during winter, they migrate to coastal waters. According to the Cornell Lab of Ornithology, they are common along the coasts of the northern United States and southern Canada during migration seasons.

These birds are piscivorous, meaning their diet consists mainly of fish. They are adept at diving and swimming underwater to catch their prey. They also consume crustaceans, insects, and amphibians. Their serrated bill helps them to grip slippery fish effectively.

Red-Breasted Mergansers are monogamous during the breeding season. They nest in sheltered locations near water, often on the ground among vegetation. The female lays 8-12 eggs and incubates them for about a month. After hatching, the ducklings are precocial and can leave the nest within a couple of days to follow their mother to water.

As of my knowledge cutoff in 2023, Red-Breasted Mergansers are not considered endangered. They are classified as "Least Concern" by the International Union for Conservation of Nature (IUCN). However, they face threats from habitat loss, pollution, and entanglement in fishing gear, which could impact their populations in the future.

Red-Breasted Mergansers are one of three merganser species in North America. They can be distinguished from the Common Merganser by their thinner, serrated bill and more defined white neck ring. Compared to the Hooded Merganser, they are larger and lack the fan-shaped crest on the head that is characteristic of the Hooded Merganser.