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Mergus merganser

(Common Merganser)


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Common Names

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Click on the language to view common names.

Common Names in Armenian:

Բադ սղոցակտուց մեծ, Մեծ Սղացակտուց Բադ

Common Names in Azerbaijani:

Böyük pazdimdik

Common Names in Bashkir:


Common Names in Basque:

Zerra handi

Common Names in Belarusian:

Вялікі савук , Крахаль вялікі

Common Names in Belarusian (Taraškievica):

Савук вялікі

Common Names in Breton:

An heskenneg bras , Heskenneg bras

Common Names in Bulgarian:

Голям нирец

Common Names in Catalan, Valencian:

Bec de serra gros

Common Names in Chinese:


Common Names in Croatian:

Veliki ronac

Common Names in Czech:

Morčák velký

Common Names in Danish:

Stor skallesluger

Common Names in Dutch:

Grote Zaagbek

Common Names in English:

Common Merganser, American goosander, American merganser, American sheldrake, big sheldrake, break horn, buff-breasted merganser, buff-breasted sheldrake, dun diver, fish duck, fishing duck, freshwater sheldrake, Goosander, greater merganser, morocco-head, pond sheldrake, sawbill, winter sheldrake

Common Names in English (United States):

Common Merganser

Common Names in Esperanto:

Granda merĝo

Common Names in Estonian:


Common Names in Faroese:


Common Names in Finnish:


Common Names in French:

grand harle, Harle bièvre

Common Names in FYRO Macedonian:

Големсеверен нуркач

Common Names in German:


Common Names in Greek:


Common Names in Hebrew:

מרגון גדול

Common Names in Hungarian:

Nagy bukó

Common Names in Irish:

Síolta mhór

Common Names in Italian:

Smergo maggiore

Common Names in Japanese:


Common Names in Kazakh:

Үлкен бейнарық

Common Names in Latvian:

Liela gaura

Common Names in Lithuanian:

Didysis dančiasnapis, Žuvinė antis

Common Names in Maltese:

Serra Prima

Common Names in Mongolian:

Хумхин нугас

Common Names in Northern Sami:


Common Names in Norwegian:


Common Names in Norwegian Nynorsk:


Common Names in Polish:


Common Names in Portuguese:

Merganso grande, Merganso-grande

Common Names in Russian:

Bolshoy Krokhal, Большой крохаль, Крохаль большой

Common Names in Sami (Northern):


Common Names in Scots Gaelic:


Common Names in Serbian:

Veliki ronac

Common Names in Slovenian:

Veliki žagar

Common Names in Spanish:

Mergo mayor, Serreta grande

Common Names in Spanish, Castilian:

Mergo mayor, Serreta Grande

Common Names in Swedish:


Common Names in Turkish:

Büyük tarakdiş

Common Names in Welsh:

Hwyaden Ddanheddog

Common Names in Western Frisian:

Grutte Seachbek


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Physical Description

Adult Female: Head : chestnut Face : Chin: white Body: Breast: white Color: gray Upperparts: white.Adult Male: Head: blackish green Bill: red Shape : slender Body: Back: black Color: white.


Adult male: Greenish-black head and upper neck · White breast, flanks and belly · Black back and upperwing coverts with white scapulars · White secondary coverts crossed with indistinct dark bar · Alternate plumage worn from fall through early summer · Male in basic eclipse plumage similar to adult female

Adult female: Red-brown head meets pale breast in crisp line of division · Well-defined white chin · White breast and belly · Pale gray body plumage


About 18 to 27 inches long, with a wingspan of 31 to 37 inches.


Usually seen in brackish marshes and freshwater ponds , rarely in salt water.

Vegetation: rivers • Minimum Elevation: 1,900 meters • Maximum Elevation: 1,900 meters • Foraging Strata: Water • Center of Abundance: Upper subtropical: higher slopes, 500-1,600 m.; subtropics. • Sensitivity to Disturbance: Medium

Typically found in a lake at a mean distance from sea level of 486.76 meters (1,596.98 feet).[1]

Ecology: Behaviour Northern breeding populations of this species are fully migratory6 although breeders in temperate regions are sedentary or only travel short distances1, 5. The species arrives on its breeding areas between March and May5, actually breeding as early as late-March (although often considerably later in more northerly regions)3. It breeds in solitary pairs or loose groups1 of up to 8-10 individuals7 (especially on islands that provide suitable nesting sites in lacustrine or coastal locations)4. The males gather to moult after mating, often undertaking considerable moult migrations to flock on key waters3. Females also undergo a post-breeding moult on the breeding grounds during which they become flightless for around 1 month4. The main migration to wintering areas largely occurs from October through to December5, mass departures being linked to the freezing of breeding and moulting areas6. Outside of the breeding season the species is typically found in small parties, with groups of up to 70 individuals feeding together on shoals of fish during the winter2. Large flocks may also form on roosting waters3, the largest gatherings occurring during the autumn migration and winter months and numbering up to several thousands of individuals3 (1,000 to 10,000 on suitable waters)6. On passage in the spring flocks are usually small however, breeding pairs remaining in flocks until they reach the breeding grounds6. Habitat Breeding The species breeds on large clear freshwater lakes1, 2, pools1, the upper reaches of rivers1, 2 and streams2 in the boreal, montane2 and temperate forest zones4. It requires waters with a fairly high productivity of fish2 surrounded by mature hard-wood trees with holes excavated by woodpeckers or natural cavities for nesting in2. Non-breeding The species winters on large unfrozen lakes , rivers , lagoons , brackish waters and marshes1, 3, generally avoiding highly saline waters3 although it may move to estuaries, coastal lagoons and sheltered sea coasts with waters less than 10 m deep in particularly harsh winters5. Diet Its diet consists predominantly of fish1 less than 10 cm long2, but may also include aquatic invertebrates (such as molluscs , crustaceans, worms, and adult and larval insects), amphibians , small mammals and birds1. Breeding site The species nests in holes excavated by large woodpeckers or natural cavities in mature hardwood trees1, 2 with entry holes more than 15 m above the ground2. It shows a preference for cavities with openings c.12 cm wide and internal diameters of c.25 cm4 in trees close to or up to 1 km away from water6. When natural tree-nesting sites are not available4 the species will use artificial nestboxes1, 2 or may nest among tree roots in undercut banks, on cliff ledges2, in rock clefts7 or in dense scrub or loose boulders on islands2. Sometimes several females may nest in the same tree3, especially on islands that provide suitable nesting sites in lacustrine or coastal locations4. Management information Artificial nestboxes commonly used are 85-100 cm high with openings 50-60 cm from the base4.


List of Habitats :


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Mostly: Fish. Lesser Quantities of: Aquatic Invertebrates





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Name Status: Accepted Name .

Last scrutiny: 23-Jan-2007

Similar Species

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Red-Breasted Merganser

Members of the genus Mergus

ZipcodeZoo has pages for 13 species and subspecies in this genus:

M. albellus (Zwergsaeger) · M. australis (Auckland Islands Merganser) · M. cucullatus (Hooded Merganser) · M. merganser (Common Merganser) · M. merganser americanus (Common Merganser (North American)) · M. merganser merganser (Common Merganser (Eurasian)) · M. merganser orientalis (Common Merganser) · M. octosetaceus (Brazilian Merganser) · M. serrator (Red-Breasted Merganser) · M. serrator linnaeus (Red-Breasted Sheldrake) · M. serrator schioleri (Red-Breasted Merganser) · M. serrator serrator (Red-Breasted Merganser) · M. squamatus (Scaly-Sided Merganser)

More Info

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Further Reading

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Data Sources

Accessed through GBIF Data Portal December 06, 2007:



  1. Standard Deviation = 572.530 based on 18,527 observations. Altitude information for each observation from British Oceanographic Data Centre. [back]
  2. BirdLife International 2009. Mergus merganser. In: IUCN 2011. IUCN Red List of Threatened Species. Version 2011.2. <>. Downloaded on 02 February 2012. [back]
Last Revised: 2015-02-06