Species Profile
Common Merganser
Mergus merganser
Quick Facts
Conservation
LCLeast ConcernAlso known as: Goosander
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Appearance
The Common Merganser is a large, streamlined duck with a distinctive long, narrow bill. Males have a dark green head, white body, and black back, while females display a grey body with a rusty cinnamon head and white chin.
Both sexes have a bright red, serrated bill and orange legs. Juveniles resemble females but with a shorter crest and duller overall colouration.
Identification & Characteristics
Male Colors
- Primary
- White
- Secondary
- Red
- Beak
- Red
- Legs
- Orange
Female Colors
- Primary
- Grey
- Secondary
- White
- Beak
- Red
- Legs
- Orange
Female Markings
Rusty-cinnamon crest, white chin
Attributes
Understanding Attributes
Rated 0–100 based on research and observation. A score of 50 is average across all bird species. These attributes are relative and don't necessarily indicate superiority.
Habitat & Distribution
Common Mergansers inhabit clear, fish-rich freshwater bodies, including lakes, rivers, and reservoirs. They are found across northern North America, Europe, and Asia, with populations extending into more temperate regions.
Some birds move to coastal areas or larger unfrozen water bodies in winter. They are widespread in Canada, the northern United States, and parts of Europe, including the UK, where they are known as Goosanders.
Distribution
Where to See This Bird
Explore regional guides for locations where this bird has been recorded.
United Kingdom
England
Scotland
Wales
Rutland
Buckinghamshire
Cumbria
Berkshire
Cheshire
Derbyshire
Durham
Essex
Herefordshire
Lancashire
Leicestershire
Lincolnshire
Manchester
Northumberland
Northamptonshire
Nottinghamshire
North Yorkshire
South Yorkshire
Tyne and Wear
West Midlands
Suffolk
Shropshire
Somerset
Staffordshire
Warwickshire
West Yorkshire
Worcestershire
Diet
Common Mergansers primarily feed on fish, using their serrated bills to grip slippery prey. They also consume aquatic invertebrates, amphibians, and occasionally small mammals or birds. These efficient predators can consume fish up to 30 cm in length.
In the past, they have been targeted by commercial fish farms following their penchant for trout and salmon, although more commonly, they will feed on the more abundant species of fish available within their immediate habitat.
Behaviour
Common Mergansers are excellent divers, using their powerful legs to propel themselves underwater in pursuit of fish. They often form small flocks during winter and engage in cooperative fishing behaviour.
These birds are generally quiet but become more vocal during courtship displays.
Calls & Sounds
Common Mergansers are generally quiet outside the breeding season. During courtship and nesting, males produce soft, grunting calls, while females make a harsh, croaking sound.
Alarm calls consist of a low, grating 'karr-karr' that can be heard during territorial disputes.
Nesting & Breeding
Breeding begins in late winter or early spring, with pairs forming on wintering grounds. Males perform elaborate courtship displays, including head-pumping and wing-flapping.
Females typically nest in tree cavities near water, sometimes using artificial nest boxes. They lay 6-13 cream-coloured eggs in a down-lined nest.
Incubation lasts about 32 days and is performed solely by the female. Ducklings leave the nest within 24 hours of hatching, often jumping from considerable heights to reach water.
Conservation
While the Common Merganser is currently listed as Least Concern, it faces threats from habitat loss and degradation of freshwater ecosystems.
Conservation efforts focus on protecting water quality and maintaining healthy fish populations in their breeding and wintering areas.
Elevation
Sea level to 2,000 meters
Additional Details
- Predators:
- Adult Common Mergansers face threats from large raptors like Bald Eagles and Great Horned Owls, while eggs and ducklings are vulnerable to raccoons, minks, and large fish.
Birdwatching Tips
- Look for them on clear, fish-rich lakes and rivers
- Observe their diving behaviour, as they can stay submerged for up to 2 minutes
- Listen for their soft, grunting calls during breeding season
- In North America, watch for them year-round in northern regions and during winter in southern areas
Did You Know?
- Common Mergansers have over 100 sharp, backward-pointing projections on their bill to help grip fish.
- They can dive to depths of up to 30 feet (9 meters) in search of prey.
- Female mergansers sometimes lay eggs in each other's nests, a behaviour known as 'egg dumping'.
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