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Bufflehead Vs Merganser: Contrasting Characteristics of North American Waterfowl

Buffleheads and Mergansers, members of the Anatidae family, are captivating waterfowl species known for their diverse characteristics and ecological roles.

While both inhabit freshwater habitats and share the common trait of being diving ducks, they exhibit remarkable differences in their size, coloration, behavior, and distribution.

Buffleheads, with their striking black-and-white plumage and distinct behaviors such as agile underwater diving, offer a unique sight in North American water bodies.

Mergansers, on the other hand, present an array of species with varying male coloration, nesting habits, and global distributions. Exploring these differences sheds light on the fascinating adaptations and interactions within the waterfowl family.

bufflehead vs merganser

Key Differences Between Bufflehead and Merganser

Buffleheads and mergansers are both types of waterfowl, but they belong to different genera and have distinct characteristics.

Here are some key differences between them:


  • Bufflehead: Buffleheads are relatively small waterfowl, measuring about 13-15 inches in length. Their compact size makes them agile divers, capable of swiftly navigating underwater to find aquatic invertebrates and small fish.
  • Merganser: Mergansers are noticeably larger, spanning 18-24 inches in length. This size variation accommodates their preference for fish-based diets. The larger body allows them to consume and digest a diet primarily consisting of fish species.

Male Coloration

  • Bufflehead: Male Buffleheads exhibit a striking contrast of colors. Their heads are glossy black, creating a dramatic backdrop for the large white patch that extends from the back of their heads down to the sides of their necks.
    This distinctive black-and-white pattern makes them easily recognizable. The sharp demarcation between the black and white areas enhances their aesthetic appeal.
  • Merganser: Male Mergansers showcase a broader range of coloration, varying between different species.
    For instance, the Common Merganser features a greenish-black head and a white neck and body. In contrast, the Hooded Merganser sports a striking black crest on its head and a contrasting white body with black accents.

Male Belly and Sides

  • Bufflehead: The male Bufflehead has a clean and crisp appearance with a white belly and sides.
    This white plumage complements their dark head and accentuates the contrast between the two colors. The overall effect is an elegant and eye-catching look that aids in identification.
  • Merganser: The male Merganser species exhibit varying colors on their sides. While Common Mergansers have white sides that harmonize with their overall coloration, Hooded Mergansers display cinnamon-colored sides.
    This difference in side coloration is one of the distinct features that set these species apart from Buffleheads and contribute to their individuality.

Female Coloration

  • Bufflehead: Female Buffleheads have a more subdued appearance compared to their male counterparts. They boast brownish plumage that blends well with their surroundings, providing effective camouflage during nesting and while caring for their young.
    A distinctive white patch around the eye and a smaller white area on the side of the head help distinguish them from other female ducks.
  • Merganser: Female Mergansers, similar to female Buffleheads, exhibit brownish hues in their plumage.
    This coloring aids in hiding them while incubating eggs or tending to their ducklings. The mottled or streaked patterns on their bodies offer further concealment, helping them avoid potential predators.

Habitat Preferences

  • Bufflehead: Buffleheads tend to favor freshwater habitats such as lakes, ponds, and slow-moving rivers. Their diving behavior and preference for aquatic invertebrates and small fish make these habitats ideal for their feeding habits. These water bodies provide both food sources and safe diving spaces.
  • Merganser: Mergansers also thrive in freshwater environments, showcasing a strong affinity for habitats with abundant fish populations. They can be found in various water bodies, including rivers, lakes, and larger ponds.
    Their ability to dive and pursue fish underwater has led them to establish themselves in habitats rich in their preferred food source.

Feeding Behavior

  • Bufflehead: Buffleheads are adept divers known for their unique feeding behavior. They plunge underwater to search for aquatic invertebrates and small fish, which constitute the majority of their diet.
    Their small size and streamlined bodies enable them to navigate through water with agility, allowing them to swiftly pursue their prey beneath the surface.
  • Merganser: Mergansers share a similar diving behavior with Buffleheads, but their feeding preferences differ. Mergansers are specialized fish-eaters. They use their long, serrated bills to catch fish underwater.
    Their bills are adapted for grasping slippery prey, showcasing a predator-prey relationship that has driven the evolution of their distinctive bill structure.

Social Behavior

  • Bufflehead: Buffleheads are often seen in small groups, displaying a somewhat gregarious social behavior. They engage in activities such as diving, feeding, and preening together. These small groups can also be observed during migration, fostering a sense of companionship and safety in numbers.
  • Merganser: Mergansers exhibit varying social behaviors depending on the species and context. They are frequently seen in pairs or small groups, especially during the breeding season. However, they can also be solitary when searching for food.
    Their social dynamics highlight their ability to adapt to different social settings based on their ecological needs.


  • Bufflehead: Buffleheads have a range primarily concentrated in North America. They breed in northern regions of North America and migrate to more temperate areas during the winter months. Their range spans from Alaska and Canada to parts of the United States, reflecting their preference for colder climates.
  • Merganser: Mergansers are more globally distributed, with various species found on different continents. Common Mergansers are found across North America, Europe, and Asia.
    Hooded Mergansers are native to North America. Their diverse range showcases the adaptability of different species to various geographical regions.

Migration Habits

  • Bufflehead: Buffleheads are migratory waterfowl, with their migration patterns influenced by the changing seasons.
    They breed in northern regions and undertake extensive migrations to reach more hospitable wintering grounds. Their migration takes them to coastal areas and other open-water bodies that remain ice-free during the colder months.
  • Merganser: Migration habits among Merganser species vary. Some species, like the Common Merganser, are migratory and undertake substantial journeys to seek suitable breeding and wintering grounds.
    Others, like the Hooded Merganser, are more resident in nature and may move to areas with open water during colder periods.

Crested Appearance (Male)

  • Bufflehead: Male Buffleheads lack a prominent crest on their heads. Their head is black with a white patch, contributing to their distinguished appearance. The absence of a crest adds to their streamlined look, underscoring their ability to navigate through water with precision.
  • Merganser: Male Mergansers, notably the Hooded Merganser, exhibit a captivating crest on their heads.
    This crest can be expanded or contracted, creating a fascinating display during courtship rituals. The crest’s striking appearance serves as a visual indicator of the male’s health and vitality, making it a crucial element of their mating behavior.

Nesting Habits

  • Bufflehead: Buffleheads often choose tree cavities as nesting sites. They nest in areas near water bodies, using existing cavities created by woodpeckers or natural hollows.
    This nesting strategy offers protection from predators and provides a secure environment for raising their young.
  • Merganser: Mergansers also nest in tree cavities, particularly in older trees near water sources. They take advantage of natural or abandoned cavities, using them as sheltered locations to lay eggs and rear their offspring.
    Their choice of nesting locations aligns with their preference for proximity to water, as they are adept swimmers and divers.

Nesting Material

  • Bufflehead: Female Buffleheads line their nesting cavities with feathers and down. These materials create a soft and insulating environment for their eggs. The use of feathers and down not only provides comfort for the developing eggs but also serves as a natural way to regulate temperature.
  • Merganser: Female Mergansers employ similar nesting materials, utilizing feathers and down to line their chosen cavities. This padding helps maintain optimal conditions for egg incubation, protecting the eggs from temperature fluctuations and potential impacts.

Brood Size

  • Bufflehead: Buffleheads typically have larger brood sizes, with clutches consisting of around 6 to 11 eggs. This reproductive strategy increases the chances of successful fledging, compensating for potential losses due to predation or environmental factors.
  • Merganser: Merganser brood sizes can vary depending on the species. Common Mergansers may have slightly larger clutches, while Hooded Mergansers often have smaller brood sizes. The number of eggs laid aligns with the specific species’ reproductive strategy and the resources available in their habitat.

Egg Color

  • Bufflehead: Bufflehead eggs are characterized by their creamy or pale coloration. This light hue blends well with the nesting materials and helps camouflage the eggs, reducing the likelihood of detection by predators.
  • Merganser: Merganser eggs typically have a whitish or pale color. This coloration serves a similar purpose to that of Bufflehead eggs, ensuring that the eggs remain inconspicuous and protected during the incubation period.


  • Bufflehead: Buffleheads communicate with soft whistles and calls. These vocalizations are used for various purposes, including maintaining contact with mates and signaling alarm. Their calls are often gentle and melodious, reflecting their generally unobtrusive nature.
  • Merganser: Mergansers also employ a variety of vocalizations. Their calls range from soft, low sounds to more distinctive and louder calls, depending on the situation. These vocalizations contribute to social interactions, pair bonding, and signaling potential threats.


  • Bufflehead: Buffleheads have a relatively limited range, primarily found in North America. They breed in northern regions, including Alaska and Canada, and migrate to more temperate areas for the winter. Coastal areas and freshwater habitats are their preferred locations during migration and wintering.
  • Merganser: Mergansers have a broader distribution, with different species found across North America, Europe, Asia, and other continents.
    Their habitat ranges vary based on the species. For instance, the Common Merganser can be found in North America, Europe, and parts of Asia, while the Hooded Merganser is native to North America.

Conservation Status

  • Bufflehead: Buffleheads generally have a stable population and are not considered endangered. Their adaptable nature and preference for a wide range of freshwater habitats contribute to their stable conservation status. However, local threats such as habitat loss and water pollution can impact their populations.
  • Merganser: The conservation status of Merganser species varies among different regions and species. While some species, like the Common Merganser, are not of immediate conservation concern due to their widespread distribution, others might face challenges.
    The Hooded Merganser, for example, is more vulnerable due to habitat loss and degradation.


  • Bufflehead: Buffleheads rarely hybridize with other species. Their specific behaviors, habitat preferences, and genetic makeup limit the opportunities for hybridization with other waterfowl.
  • Merganser: Mergansers, due to their broader range and interactions with related species, may occasionally hybridize with other merganser species. Hybridization can occur between species like the Common Merganser and the Red-breasted Merganser, leading to varying characteristics in the resulting hybrids.

Scientific Classification


  • Family: Anatidae (Ducks, Geese, Swans).
  • Genus: Bucephala.
  • Species: B. albeola.


  • Family: Anatidae (Ducks, Geese, Swans).
  • Genus: Mergus.

Various species include M. merganser (Common Merganser), M. serrator (Red-breasted Merganser), and Lophodytes cucullatus (Hooded Merganser).

Bufflehead Vs Merganser: Comparison Table

SizeSmaller (13-15 inches)Larger (18-24 inches)
Male ColorationBlack head, white neckVaried (greenish-black, black crest, etc.)
Male Belly and SidesWhiteWhite or cinnamon sides
Female ColorationBrown with white patchesBrown with mottling/streaking
Habitat PreferencesFreshwater habitatsFreshwater habitats
Feeding BehaviorDives for invertebrates, fishDives for fish
Social BehaviorGenerally seen in small groupsOften seen in pairs or small groups
RangeNorth AmericaGlobal distribution
Migration HabitsMigratoryMigratory or resident
Crested Appearance (Male)No crestSome species have crests
Nesting HabitsNest in tree cavitiesNest in tree cavities
Nesting MaterialUse feathers and downUse feathers and down
Brood SizeUsually 6-11 eggsVaries by species
Egg ColorCreamy or paleWhitish or pale
VocalizationsSoft whistles and callsVarious calls
RangeNorth AmericaGlobal distribution
Conservation StatusGenerally stableSome species vulnerable
HybridizationRarely hybridizeRare hybridization
Scientific ClassificationGenus BucephalaGenus Mergus

Frequently Asked Questions

What is the primary reason for the difference in male Mergansers’ side coloration?

The difference in male Mergansers’ side coloration is primarily due to species-specific adaptations and visual cues for mate attraction.
For instance, Common Mergansers have white sides that might help attract females by displaying their cleanliness and health, while Hooded Mergansers’ cinnamon sides could serve as a visual signal of their vitality and breeding readiness.

Are Buffleheads and Mergansers affected by the same conservation threats?

While both Buffleheads and Mergansers can face habitat loss and water pollution, the extent of these threats can vary.
Buffleheads, with their stable populations and adaptable nature, might be less susceptible. Mergansers, especially species with more limited ranges, could be more vulnerable to habitat degradation due to their specific requirements for nesting and feeding areas.

Do Buffleheads and Mergansers share similar vocalizations?

While both Buffleheads and Mergansers communicate using vocalizations, their specific calls differ. Buffleheads are known for their soft whistles and melodic calls, which are distinct from the vocalizations of Mergansers. Mergansers often have a broader range of calls, including low sounds and more noticeable calls that serve various social and environmental purposes.

Can hybridization impact the genetic diversity of Merganser populations?

Yes, hybridization among Merganser species can impact genetic diversity. When different species interbreed, the genetic traits of each parent species can mix, potentially creating hybrids with unique characteristics.
While some hybrids might be well-suited to certain environments, others could face challenges in terms of fitness and adaptation, affecting the overall genetic diversity of Merganser populations.

How do Buffleheads and Mergansers contribute to aquatic ecosystems?

Buffleheads and Mergansers play essential roles in aquatic ecosystems as consumers and predators. Buffleheads feed on aquatic invertebrates and small fish, contributing to the regulation of prey populations.
Mergansers, with their fish-eating behavior, help control fish populations in freshwater habitats. Both species contribute to the balance of food webs and energy flow within their respective ecosystems.

To Recap

The contrasting features and behaviors of Buffleheads and Mergansers illustrate the rich diversity that characterizes the avian world.

From their distinct coloration and nesting habits to their vocalizations and migration patterns, these waterfowl exemplify the intricate interplay between evolutionary adaptations and environmental niches.

Their roles as predators and contributors to aquatic ecosystems further emphasize their importance in maintaining ecological balance.

As we continue to delve into the intricacies of these avian species, we gain a deeper appreciation for the natural world’s complexity and the marvels it holds within its diverse inhabitants.

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