Common Merganser – Profile | Traits | Facts | Diet | Breeding

Common merganser

Common Merganser is a Large, modern diving duck with black upperparts and white underparts. Head and higher neck are green-black with head crest normally not seen. Long, the skinny bill is brilliant red. Wings are black with in-depth white patches. Feeds on fish, mollusks, crustaceans, bugs, and crops.

Common Merganser Profile

Common Merganser is Common all through a lot of North America. Breeds from eastern Alaska to Newfoundland on wooded rivers, ponds, and lakes.

Resident in Northern New England, southern Ontario, and Quebec, and within the western states. Spends winters in the south so far as Mexico, primarily on massive lakes and rivers, often on saltwater.

This fish-eating duck is the typical merganser of freshwater lakes. Its flocks are normally small, however, these might mix into massive concentrations typically at massive reservoirs.

Common Mergansers residing alongside rivers might spend hours resting on rocks or onshore. The British call this bird the “Goosander.”

In some components of Europe, with artificial nesting sites supplied, the species has change into a typical nesting bird alongside city waterfronts; this has not but occurred in North America.

Common Merganser

Common Merganser Geographic Range

Mergus merganser (common mergansers or goosanders) happens in the Nearctic and Palearctic areas. Although their abundance has been lowering in North America, they’re nonetheless essentially the most plentiful of the mergansers discovered there.

In North America, widespread mergansers might breed as far north as southern Alaska and Canada. Some happen year-round within the northern and western United States.

North American birds winter in New England, midwestern and southern states, and the Pacific coast of the U.S. and Canada. Common mergansers within the Palearctic area sometimes breed in northern Europe, Scandinavia, all through Russia, and in a lot of northern Asia.

Populations in Europe winter alongside the coasts of Scandinavia and northern Europe, in addition to components of the northern Mediterranean coast and north Africa. In Asia widespread mergansers winter in southern Asia, northern India, Japan, China, and Korea.

Common Merganser Habitat

Common mergansers choose to live in wooded areas alongside streams and rivers or close to small, inland lakes. They can be discovered alongside the shores of the Great Lakes, in addition to on coastal streams in British Columbia.

Nests are sometimes in a crevice of a deciduous tree alongside the shore, however typically shall be in different kinds of crevices or on the ground, under tangled bushes. Mergansers may additionally occupy deserted hawk nests when obtainable.

Common mergansers are diving predators who find their prey by sight, and subsequently are inclined to feed in clear waters, lower than 4 m deep, together with estuaries, coastal bays, lakes, streams, and rivers.

In the winter, widespread mergansers have been identified to dive deeper with the intention to seize education fish.

Common Merganser Physical Description

Common mergansers are the most important mergansers and the most important North American inland geese. Males are barely bigger, on average.

Males and females are colored fairly in another way. Males have brilliant, vivid, strong areas of color with sharply outlined edges; black back, darkish green to blackhead (modifications to brown in non-breeding season), serrated red bill, red feet, and white, cylindrical body with slight peach-colored tinge on breast, and fading to some gray within the tail. Male widespread mergansers haven’t any seen crest.

Males could be readily distinguished from male widespread goldeneyes, which have shorter necks, rounded bodies, more ruffled heads, and white eyes.

Female common mergansers have the same red feet and bill as males, however, they have a bigger crest, a brown head, and the body is a much less sharply outlined combination of gray and white, fading to white within the breast.

The line between the brown neck and white breast is sharply outlined, which distinguishes feminine widespread mergansers from related feminine red-breasted mergansers.

Adults have an average basal metabolic rate of 638 kJ/d. Field metabolic charges, studied in autumn in Scotland, had been discovered to be higher in females than males, with an overall average of two.32 ml CO2/h.


The record for the oldest widespread merganser is held at 13 years 5 months, however, banding records point out most longevities of roughly 12 years 6 months for males and 13 years 10 months for females.

Common Merganser Movements

The species is a partial migrant, with birds shifting away from areas the place rivers and main lakes freeze within the winter, however resident the place waters stay open.

Eastern North American birds transfer south in small teams to the United States wherever ice-free situations exist on lakes and rivers; on the milder Pacific coast, they’re everlasting residents.

Scandinavian and Russian birds additionally migrate southwards, however western European birds, and some in Japan, are largely resident.

In some populations, the males additionally present distinct moult migration, leaving the breeding areas as quickly because the younger hatch to spend the summer season (June to September) elsewhere.

Notably, many of the western European male population migrates north to estuaries in Finnmark in northern Norway (principally Tanafjord) to moult, leaving the females to look after the ducklings. Much smaller numbers of males additionally use estuaries in eastern Scotland as a moulting area.

Common Merganser

Common Merganser Facts

Common Mergansers are the most important of the three merganser species in North America.

Gulls typically observe flocks as they forage. They look forward to the geese returning to the floor with fish, after which they attempt to steal their prey. Occasionally a Bald Eagle will try this.

These massive fish-eaters have serrated edges to their bills to assist them to grip their prey. Along with the Smew and the opposite Mergansers, they’re typically referred to as “sawbills.”

A gaggle of geese has many collective nouns, together with a “brace”, “flush”, “paddling”, “raft”, and “team” of geese.

Common Merganser Feeding Behavior

Forages by diving and swimming underwater, propelled by its feet, stroking with each foot in unison. Finds most meals by sight; might swim alongside the floor, dipping head underwater repeatedly till prey is spotted, then diving in pursuit.

Like the opposite mergansers, these piscivorous geese have serrated edges to their bills to assist them to grip their prey, so they’re typically referred to as “sawbills”.

In addition to fish, they take a large range of different aquatic prey, akin to molluscs, crustaceans, worms, insect larvae, and amphibians; more not often, small mammals and birds could also be taken.

As indifferent birds with the character, the salmon-pink tinge proven variably by males might be diet-related, obtained from the carotenoid pigments present in some crustaceans and fish.

When not diving for meals, they’re normally seen swimming on the water floor, or resting on rocks in midstream or hidden amongst riverbank vegetation, or (in winter) on the sting of floating ice.

In most locations, the widespread merganser is as a lot a frequenter of saltwater as recent water. In bigger streams and rivers, they float down with the stream for a couple of miles, and both fly back once more or more generally fish their approach back, diving incessantly the whole approach.

In smaller streams, they’re present in pairs or smaller teams, they usually float down, twisting round and round within the rapids, or fishing vigorously in a deep pool close to the foot of a waterfall or speedy.

When floating leisurely, they place themselves in water much like geese, however in addition they swim deep in water like cormorants, particularly when swimming upstream.

They typically sit on a rock in the midst of the water, much like cormorants, typically half-opening their wings to the sun. To rise from the water, they flap alongside the floor for many yards.

Once they’re airborne, the flight is robust and speedy. They typically fish in a gaggle forming a semicircle and driving the fish into shallow water, the place they’re captured simply.

Their atypical voice is a low, harsh croak, however, in the course of the breeding season, they (together with the younger) make a plaintive, soft whistle.

Generally, they’re cautious, and one or more birds keep on sentry obligation to warn the flock of approaching danger. When disturbed, they typically disgorge meals before shifting.

Though they transfer clumsily on land, they resort to operating when pressed, assuming a really upright place much like penguins, and falling and stumbling continuously.


Common Merganser feeds on Largely fish. Eats all kinds of fish; additionally will eat mussels, shrimp, salamanders, not often plant materials. Adult males might swallow fish more than 1 foot long. Young ducklings eat largely aquatic bugs.

Common Merganser


8-11, typically 6-13. Pale buff. Females typically lay eggs in every others’ nests. Incubation is by feminine solely, 30-35 days. Young: May stay in the nest a day or more after hatching; then they climb to cavity entrance and leap to the ground.

Female tends younger birds for a number of weeks, however younger feed themselves; they might survive even when deserted fairly early. Young are able to fly about 65-70 days after hatching.


Common Merganser may stay in the nest a day or more after hatching; then they climb to the cavity entrance and leap to the ground. Female tends younger birds for a number of weeks, however younger feed themselves; they might survive even when deserted fairly early. Young are able to fly about 65-70 days after hatching.

Common Merganser Behavior

Mergus merganser is a social species, preferring to be in teams of as much as 75 people. Nest sites are normally remoted, however, females typically nest in shut proximity and even within the same tree. Broods typically intermix, producing blended broods of as much as 40 or younger, tended by one or more adult females.

In the winter, big gatherings of tons of people have been noticed. Birds in flocks have a tendency to take care of regular spacing in flight, however, on the water massive teams will distribute irregularly, with pairs remaining shut.

Common mergansers fly individually, in pairs, or in small flocks. They sometimes fly at about 70 km/h, and maintain the top, body, and legs in a single horizontal line.

Females simply maneuver between bushes in quest of nesting sites, however, the flight is usually both low and alongside waterways or high and directional.

Common mergansers swim alongside the floor of clear shallow waters, paddling alternately, with their heads submerged with the intention to see their prey. Their dive is preceded by a slight leap.

When diving, Mergus merganser people use solely their feet for propulsion, paddling in unison. In bigger teams, one individual might lead others by initiating a gaggle dive, however, in small groups, people are inclined to dive independently.

Common mergansers are able to remain underwater for as much as 2 minutes, however, most recorded dive occasions are 52 seconds in 2 to three m water and 37 seconds in 18 to 37 m water, with the standard dive lasting lower than 30 seconds.

Common Merganser

Common Merganser Home Range

Nesting sites are normally separated from each other, but widespread mergansers have additionally been identified to nest in shut proximity in some circumstances, with as many as 10 females nesting in a single tree.

Territorial behavior is minimal, with males often defending favorite loafing sites close to the nest. Mergus merganser people feed over a big range, searching for a medium to massive bodies of clear water. Females will lead younger as much as 8 km downstream with the intention to feed in bigger bodies of water.

Common Merganser Communication

Common mergansers use their eager eyesight to find prey underwater whereas swimming on the floor, however, may also revert to probing underwater crevices when the water is cloudy.

Males are sometimes solely vocal throughout the courtship, and have a number of calls, together with hoarse croaking sounds and a twang considerably like a guitar string.

Females are additionally predominantly silent, vocalizing solely in courtship or as a warning of danger. The females have a harsh karr, karr call.

Aerial chases, through which 2 or more birds dive from flight into the water with a selected body posture to supply an audible hole sound, have been reported, however, their function is unknown.

Common Merganser Food Habits

Common mergansers are expert diving predators, consuming primarily slower small fish. Their serrated bills are properly-suited to capturing small fish and different aquatic prey.

Clearwater is most well-liked for feeding as a result of the birds hunt primarily by sight. When fish are scarce (normally in spring), mergansers will substitute different small aquatic prey akin to bugs, frogs, and snails.

They have been identified to eat aquatic crops in some situations, and to feed on trout from freshwater streams when close by ponds and lakes freeze. These birds feed most actively within the early morning after daybreak, within the afternoon, and before sundown.

Common Merganser

Common Merganser Predation

Common mergansers are usually thought to be top predators in aquatic meal chains. Predation charges are very low, and their offspring survival rate is nice, largely as a result of Mergus merganser sometimes nests far sufficient north that almost all widespread nest predators will not be a menace.

The nest predators that live far sufficient north to probably be a menace to Mergus merganser embody red squirrels, American martens, northern glints, and black bears.

Large predatory fish akin to northern pike, together with predatory birds akin to bald and golden eagles, widespread loons, and a few owls and hawks, might prey on more susceptible, immature mergansers. However, no predators of widespread mergansers have been documented.

Common Merganser Ecosystem

Mergus merganser is taken into account as a keystone predator, performing to control the populations of many inland fish akin to perch and bass. By thinning these populations, it’s thought that mergansers preserve lakes and ponds below their carrying capacity.

This permits these fish that survive to thrive and develop, whereas, in lakes and ponds missing the merganser predation, fish are sometimes too prolific and convey about their very own growth stagnation.

Thus, wilderness lakes the place mergansers feed usually produce bigger, more healthy fish than lakes without predation, the place no individual fish develop very properly due to overcrowding.

Brood parasitism, or egg-dumping, is pretty widespread between individual widespread mergansers, in addition to between Mergus merganser and different associated species.

Common mergansers have been identified to parasitize and be parasitized by each widespread goldeneyes and hooded mergansers. This has been proven to result in blended clutches of as much as 19 eggs.


Common Merganser courtship shows of males embody swimming very quickly in circles close to feminine; instantly stretching neck upward, pointing bill straight up, and giving a soft call.

Nest site is close to water, normally in a massive tree cavity; additionally in crevices in the rock, in holes under tree roots or undercut banks, or in nest bins. Occasionally in buildings. Nest of wooden chips or particles in the cavity, plus lining of down.

Common Merganser Reproduction

Common mergansers kind monogamous mating pairs that final for no less than one mating season. The period of those loyalties is unknown, however, pairs reunite over years in different duck species.

Pairs are fashioned in late winter when a male circles a feminine and shows the Courtship-Intent Posture, with neck stretched ahead and head feathers erect.

Common mergansers breed as soon as per year, in the summertime. A clutch sometimes accommodates 9 to 12 eggs, that are laid between May and June.

Eggs are roughly 64 mm in size and have a pale yellow, ivory, or white buff look. Upon hatching, younger birds observe their moms to feeding sites.

Often the mom will lead the brood to bigger bodies of water downstream to feed. Young can swim and feed simply as quickly as they go away the nest, though for the first few days most meals are obtained on the floor.

Within about 8 days, the younger are skillful divers. Mothers abandon their broods before the younger develop the power to fly, sometimes 30 to 50 days after hatching.

Common Merganser

Young mergansers generally are part of different broods after being deserted; blended broods of more than 40 younger have been noticed.

Male parents sometimes go away to the breeding grounds when incubation begins, and feminine parents incubate the eggs for 28 to 35 days. Young are precocial and go away from the nest within 24 to 48 hours.

When the nest is in a tree cavity, this departure is completed by leaping to the ground. For the next few weeks, females could be seen main their chicks to feeding sites as distant as 8 km, though as soon as they arrive there, the younger are chargeable for discovering their very own meals.

The mom might give warnings of potential risks, to which the younger are fairly responsive, however, otherwise, the younger is pretty impartial on the feeding site.

They are expert divers inside 8 days of leaving the nest, till then they dabble on the floor to search out meals. Mothers abandon their offspring before the younger birds develop the power to fly.

Common Merganser Conservation

The Common Merganser is a big duck that can even be referred to as the goosander or gulaund. It prefers to reside in Europe, northern Asia, and North America and is continuously seen close to lakes and rivers. Nests are made inside current holes in bushes within the surrounding areas, and could also be left by prior resident species.

The Common Merganser eats primarily fish and is taken into account a “sawbill” as a result of the serrated bill which helps to catch them. These geese additionally eat mussels, shrimp, younger birds, and insects.

During the winter months, northern populations will migrate to ice-free southern zones close to lakes and ponds. The conservation ranking for this species is Least Concern.

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