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The Common Merganser, a striking waterfowl, is a species that captivates the attention of bird enthusiasts and ecologists alike. Its sleek, slender build and vibrant plumage make it a standout among its feathered counterparts.

From the distinctive appearance of breeding males to the graceful diving behavior they exhibit while hunting for fish, the Common Merganser presents a fascinating subject for study.

This species' migratory habits and its interactions with its environment raise questions about its adaptability and the challenges it faces in the modern world.

Key Takeaways

  • Common Mergansers can be identified by their distinctive plumage, with males having a dark green head and mostly white body, while females have a tufted red-brown head, gray body, and white throat.
  • They are native to North America and have sleek bodies and long narrow bills with serrated edges.
  • Common Mergansers are skilled divers and use their diving abilities to catch fish, often forming small flocks during the non-breeding period.
  • During the breeding season, male Common Mergansers display iridescent feathers, particularly on their dark green heads, which serve as visual cues in courtship displays. They nest in tree cavities near open water bodies.

Merganser Identification Overview

identifying merganser species details

The Merganser Identification Overview directly answers the main query through an examination of the distinct plumage characteristics, behaviors, and physical features that differentiate male and female Common Mergansers.

The male Merganser is identifiable by a dark green head and predominantly white body. The female, on the other hand, displays a rusty brown head and gray body, accompanied by a white throat.

These birds, native to North America, are recognized by their sleek bodies, long, narrow bills with serrated edges, and thin red bills. Their behavior showcases diving skills used to catch fish and the formation of small flocks in the non-breeding period. During the breeding season, their courtship displays are noteworthy.

Common Mergansers are often seen in rivers, lakes, and large ponds, diving underwater for fish. They usually nest in tree cavities near water bodies.

This overview is a practical resource for bird enthusiasts and researchers.

Merganser Plumage Description

The Common Merganser, a bird species with a unique appearance, has different plumage patterns in North America and Eurasia.

In North America, males have dark green heads, females have tufted red-brown heads, and the body in both sexes is mostly white with a peachy blush on the underparts. Alternatively, Eurasian males display a green head, females have a rusty brown head, and the body color remains identical to their North American counterparts.

During the breeding season, plumage changes occur: males exhibit a dark green head and a mostly white body with a peachy blush on the underparts, while females and immature males show a rusty brown head and gray bodies with a cleanly demarcated white throat.

The elongated appearance of this bird species becomes more apparent when they fly close to the water's surface in trailing lines.

Anatomy and physiology

study of body structure

The anatomy and physiology of the Common Merganser is characterized by a long, narrow bill with serrated edges and a less stocky build compared to other duck species.

The male Common Mergansers are characterized by a greenish-black crested head, while the female counterparts display a tufted red-brown head.

The diet of these ducks includes fish, amphibians, and invertebrates, which they commonly retrieve by diving underwater in both marine and freshwater habitats.

The average length of the Common Merganser can vary between 22.9 to 25.5 inches. Males can weigh around 3.64 lbs and females around 2.73 lbs.

The combination of a sleek body, thin red bill, and unique regional plumage variations make them intriguing subjects in the northern lakes and rivers they inhabit.

Iridescent Feathers on Males

glistening plumage of males

Male Common Mergansers display iridescent feathers, primarily during the breeding season. This striking feature presents in the form of dark green iridescent heads and predominantly white bodies with a peachy blush on the underparts. These feathers act as a visual cue in courtship displays, adding to the vibrant spectacle of nature's artistry.

The setting for this display is typically tree cavities near open water bodies such as rivers and lakes, which serve as their nesting grounds. Here, the male Common Mergansers exhibit their dazzling plumage, especially while diving and swimming underwater in pursuit of fish.

The iridescent green heads of these birds set them apart from other species, like Mallards, aiding bird enthusiasts in identifying and admiring them. The males' iridescent plumage, when observed during their feeding behavior and migration, further underscores the alluring charm of the Common Merganser.

Courtship and Mating Displays

lovebirds intricate courtship rituals

Common Mergansers, especially males, participate in intricate courtship and mating displays. Males demonstrate behaviors such as head-throwing, bowing, and neck movements to attract females. During these rituals, males swim in circles around females, showcasing their striking plumage and raised green crests.

Courtship flights are also a part of the display, with males soaring above water, emitting distinct calls to attract potential mates. These actions, both visual and auditory, indicate the male's fitness and capability to care for offspring.

Female Common Mergansers may reciprocate with mutual preening and head-bobbing, indicating acceptance of the mate. These elaborate courtship behaviors are commonly witnessed in North America's Great Lakes region.

Winter Migration Patterns

birds winter migration routes

Common Mergansers, hardy birds, migrate in small groups during late fall and early spring. Their migration patterns take them as far north as open water allows, even in winter. They are often seen along the Atlantic coast from Newfoundland to Florida and from the Great Lakes to the Gulf of Mexico.

In New England and New York, they inhabit lakes, large rivers, and some coastal bays during winter. Climate change impacts their environment and their winter migration patterns are being studied closely using climate models and bird observations.

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Mating Call Sound Description

The mating call sound of the male Common Merganser is characterized by a resonant, low-pitched croak. This distinctive sound, reminiscent of a deep, hoarse growl or grunt, serves two primary purposes: courtship behavior and territorial communication during the breeding season.

The call's low, raspy, and guttural quality allows it to carry over long distances, making it effective for attracting females and marking territory. Males are generally louder compared to females. This distinctive call aids birdwatchers in identifying the presence of Common Mergansers in their breeding habitat, especially in the North.

The Cornell Lab provides a guide to further aid in identifying these predominantly white, striking birds. The mating call of the male Common Merganser, thus, plays a significant role in their breeding behavior.

Frequently Asked Questions

How Rare Is a Common Merganser?

The Common Merganser is not a rare species. This is supported by the facts that they inhabit various environments and have a large global breeding population, estimated at 1.9 million. Therefore, the notion of their rarity is contradicted.

Is a Common Merganser a Duck?

The Common Merganser is a duck. This distinct classification results from its long, slim body and its diving habits. Its living environment comprises rivers, lakes, and large ponds. The feature that sets it apart from other ducks is its long, slim beak with serrated edges.

What Is Another Name for a Common Merganser?

The common merganser, Mergus merganser, is also referred to as the goosander. This bird, known for its streamlined shape and impressive fishing skills, is often called the sheldrake or sawbill.

What Is the Difference Between a Hooded Merganser and a Common Merganser?

The difference between a Hooded Merganser and a Common Merganser lies in their appearance, size, habitat preference, and feeding behavior. The Hooded Merganser exhibits a distinctive crest and has a tendency to inhabit wooded swamps. The Common Merganser, on the other hand, is larger in size and typically found in open water habitats.

Are Common Murre and Common Merganser Related Species?

Yes, the common murre bird species and the common merganser are two different species. The common murre is a seabird in the auk family, while the common merganser is a large species of duck. They are not closely related in terms of taxonomy or genetics.


In conclusion, the Common Merganser is a striking and adaptable species of duck. They are known for their diving behavior and preference for fish as a primary food source. With their sleek bodies and vibrant plumage, these birds are a beautiful sight to behold in their natural habitats.

Their resilience in the face of various threats to their environment is a testament to their importance in the ecosystem.