The common merganser (North American) or goosander (Eurasian) (''Mergus merganser'') is a large
seaduck
The sea ducks (''Mergini'') are a tribe of the duck subfamily of birds, the Anatinae. The taxonomy of this group is incomplete. Some authorities separate the group as a subfamily, while others remove some genera. Most species within the group sp ...
of rivers and lakes in forested areas of Europe, Asia, and North America. The common merganser eats mainly fish. It nests in holes in trees.
Taxonomy
The first
formal description of the common merganser was by Swedish naturalist
Carl Linnaeus in 1758 in the
10th edition of his ''
Systema Naturae''. He introduced the current
binomial name
In taxonomy, binomial nomenclature ("two-term naming system"), also called nomenclature ("two-name naming system") or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, bot ...
''Mergus merganser''. The genus name is a
Latin word used by
Pliny
Pliny may refer to:
People
* Pliny the Elder (23–79 CE), ancient Roman nobleman, scientist, historian, and author of ''Naturalis Historia'' (''Pliny's Natural History'')
* Pliny the Younger (died 113), ancient Roman statesman, orator, w ...
and other
Roman
Roman or Romans most often refers to:
* Rome, the capital city of Italy
* Ancient Rome, Roman civilization from 8th century BC to 5th century AD
*Roman people, the people of ancient Rome
*''Epistle to the Romans'', shortened to ''Romans'', a lett ...
authors to refer to an unspecified waterbird, and ''merganser'' is derived from ''mergus'' and ''anser'', Latin for "goose".
In 1843
John James Audubon used the name "Buff-breasted Merganser" in addition to "goosander" in his book ''
The Birds of America
''The Birds of America'' is a book by naturalist and painter John James Audubon, containing illustrations of a wide variety of birds of the United States. It was first published as a series in sections between 1827 and 1838, in Edinburgh an ...
''.
[
The three subspecies differ in only minor detail:][
* ''M. m. merganser'' – Linnaeus, 1758 is found throughout northern Europe and northern Asiatic Russia.
* ''M. m. orientalis'' – ]Gould
Gould may refer to:
People
* Gould (name), a surname
Places United States
* Gould, Arkansas, a city
* Gould, Colorado, an unincorporated community
* Gould, Ohio, an unincorporated community
* Gould, Oklahoma, a town
* Gould, West Virginia, ...
, 1845 (syn. ''M. m. comatus'' – Salvadori, 1895) is found in the Central Asian mountains. Slightly larger than ''M. m. merganser'', it has a more slender bill.
* ''M. m. americanus'' – Cassin, 1852 is found in North America. Its bill is broader-based than in ''M. m. merganser'', and a black bar crosses the white inner wing (visible in flight) on males.
Description
It is long with a wingspan and a weight of ; males average slightly larger than females, but with some overlap. Like other species
In biology, a species is the basic unit of Taxonomy (biology), classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of ...
in the genus ''Mergus
''Mergus'' is the genus of the typical mergansers , fish-eating ducks in the subfamily Anatinae. The genus name is a Latin word used by Pliny the Elder and other Roman authors to refer to an unspecified waterbird.
The common merganser (''Merg ...
'', it has a crest of longer head feathers, but these usually lie smoothly rounded behind the head, not normally forming an erect crest. Adult males in breeding plumage are easily distinguished, the body white with a variable salmon-pink tinge, the head black with an iridescent green gloss, the rump and tail grey, and the wings largely white on the inner half, black on the outer half. Females and males in "eclipse" (non-breeding plumage, July to October) are largely grey, with a reddish-brown head, white chin, and white secondary feathers on the wing. Juveniles (both sexes) are similar to adult females but also show a short black-edged white stripe between the eye and bill. The bill and legs are red to brownish-red, brightest on adult males, dullest on juveniles.[
]
Behaviour
Feeding
Like the other mergansers, these piscivorous ducks have serrated edges to their bills to help them grip their prey, so they are often known as "sawbills". In addition to fish, they take a wide range of other aquatic prey, such as molluscs, crustacean
Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean group ...
s, worms, insect larvae, and amphibians; more rarely, small mammals and birds may be taken.[ As in other birds with the character, the salmon-pink tinge shown variably by males is probably diet-related, obtained from the ]carotenoid
Carotenoids (), also called tetraterpenoids, are yellow, orange, and red organic pigments that are produced by plants and algae, as well as several bacteria, and fungi. Carotenoids give the characteristic color to pumpkins, carrots, parsnips, ...
pigments present in some crustaceans and fish.[ When not diving for food, they are usually seen swimming on the water surface, or resting on rocks in midstream or hidden among riverbank vegetation, or (in winter) on the edge of floating ice.][
In most places, the common merganser is as much a frequenter of salt water as fresh water. In larger streams and rivers, they float down with the stream for a few miles, and either fly back again or more commonly fish their way back, diving incessantly the whole way. In smaller streams, they are present in pairs or smaller groups, and they float down, twisting round and round in the rapids, or fishing vigorously in a deep pool near the foot of a waterfall or rapid. When floating leisurely, they position themselves in water similar to ducks, but they also swim deep in water like cormorants, especially when swimming upstream. They often sit on a rock in the middle of the water, similar to cormorants, often half-opening their wings to the sun. To rise from water, they flap along the surface for many yards. Once they are airborne, their flight is strong and rapid.][ They often fish in a group forming a semicircle and driving the fish into shallow water, where they are captured easily. Their ordinary voice is a low, harsh croak, but during the breeding season, males in display, as well as young, make a plaintive, soft whistle. Generally, they are wary, and one or more birds stay on sentry duty to warn the flock of approaching danger. When disturbed, they often disgorge food before moving.][ Though they move clumsily on land, they resort to running when pressed, assuming a very upright position similar to penguins, and falling and stumbling frequently.][
]
Breeding
Nesting is normally in a tree cavity, so it requires mature forest as its breeding habitat; they also readily use large nest boxes where provided, requiring an entrance hole in diameter.[ In places devoid of trees (like Central Asian mountains), they use holes in cliffs and steep, high banks, sometimes at considerable distances from the water.][ The female lays 6–17 (most often 8–12) white to yellowish eggs, and raises one brood in a season. The ducklings are taken by their mother in her bill to rivers or lakes immediately after hatching, where they feed on freshwater invertebrates and small fish fry, fledging when 60–70 days old. The young are sexually mature at the age of two years.][ Common mergansers are known to form crèches, with single females having been observed with over 70 ducklings at one time.][
]
Movements
The species is a partial migrant, with birds moving away from areas where rivers and major lakes freeze in the winter, but resident where waters remain open. Eastern North American birds move south in small groups to the United States wherever ice-free conditions exist on lakes and rivers; on the milder Pacific coast, they are permanent residents. Scandinavian and Russia
Russia (, , ), or the Russian Federation, is a transcontinental country spanning Eastern Europe and Northern Asia. It is the largest country in the world, with its internationally recognised territory covering , and encompassing one-eight ...
n birds also migrate southwards, but western European birds, and a few in Japan, are largely resident.[ In some populations, the males also show distinct moult migration, leaving the breeding areas as soon as the young hatch to spend the summer (June to September) elsewhere. Notably, most of the western European male population migrates north to estuaries in ]Finnmark
Finnmark (; se, Finnmárku ; fkv, Finmarku; fi, Ruija ; russian: Финнмарк) was a county in the northern part of Norway, and it is scheduled to become a county again in 2024.
On 1 January 2020, Finnmark was merged with the neighbour ...
in northern Norway (principally Tanafjord
The Tanafjord or Tanafjorden ( sme, Deanuvuotna) is a large fjord in Troms og Finnmark county, Norway. It is located in the municipalities of Tana, Gamvik, and Berlevåg. Its orientation is mainly north–south, reaching approximately from the ...
) to moult, leaving the females to care for the ducklings. Much smaller numbers of males also use estuaries in eastern Scotland as a moulting area.[
]
Status and conservation
Overall, the species is not threatened, though illegal persecution by game-fishing interests is a problem in some areas.[ In February 2020, a rare common merganser sighting was documented in ]Central Park, New York
Central Park is an urban park in New York City located between the Upper West and Upper East Sides of Manhattan. It is the fifth-largest park in the city, covering . It is the most visited urban park in the United States, with an estimated 42 ...
; the bird was in obvious distress, with its beak being trapped by a piece of debris.
Within western Europe, a marked southward spread has occurred from Scandinavia in the breeding range since about 1850, colonising Scotland in 1871, England in 1941, and also a strong increase in the population in the Alps
The Alps () ; german: Alpen ; it, Alpi ; rm, Alps ; sl, Alpe . are the highest and most extensive mountain range system that lies entirely in Europe, stretching approximately across seven Alpine countries (from west to east): France, Sw ...
.[ They are very scarce in Ireland, with regular breeding confined to a few pairs in County Wicklow.][Report of the Irish Rare Breeding Birds Panel 2013 ''Irish Birds'' Vol. 10 p.65]
The goosander is one of the species to which the applies.
References
External links
*
*
{{Authority control
common merganser
The common merganser (North American) or goosander (Eurasian) (''Mergus merganser'') is a large seaduck of rivers and lakes in forested areas of Europe, Asia, and North America. The common merganser eats mainly fish. It nests in holes in trees. ...
common merganser
The common merganser (North American) or goosander (Eurasian) (''Mergus merganser'') is a large seaduck of rivers and lakes in forested areas of Europe, Asia, and North America. The common merganser eats mainly fish. It nests in holes in trees. ...
Holarctic birds
common merganser
The common merganser (North American) or goosander (Eurasian) (''Mergus merganser'') is a large seaduck of rivers and lakes in forested areas of Europe, Asia, and North America. The common merganser eats mainly fish. It nests in holes in trees. ...
common merganser
The common merganser (North American) or goosander (Eurasian) (''Mergus merganser'') is a large seaduck of rivers and lakes in forested areas of Europe, Asia, and North America. The common merganser eats mainly fish. It nests in holes in trees. ...
Extant Pleistocene first appearances