Greater Scaup
Aythya marila
Visual Identification
Appearance
The Greater Scaup is a medium-sized diving duck with a distinctive rounded head and blue-grey bill. Males in breeding plumage have a glossy black head, neck, and breast, contrasting with a white body and grey back. The wings feature white patches visible in flight.
Females are predominantly brown, with a white patch at the base of the bill. Both sexes have yellow eyes. In non-breeding plumage, males resemble females but retain darker head coloration.
Juvenile scaup are similar in appearance to females but have less vivid white facial markings and are a duller, paler shade of brown all over.
Size
Length
39cm to 56cm
Wingspan
71cm to 84cm
Weight
726g to 1.36kg
Habitat and Distribution
Habitats
Woodland
Garden
Wetland
Coastal
Urban
Farmland
Grassland
Desert
Tundra
Rainforest
Mountain
Savanna
Distribution
Greater Scaups inhabit coastal marine areas, large lakes, and deep freshwater marshes. They breed in the boreal and subarctic regions of North America and Eurasia, including Alaska, Canada, and northern Europe.
During winter, they migrate to coastal areas and large inland water bodies. In North America, they are common along both coasts and the Great Lakes- mainly to the Atlantic coast states of Delaware, Maryland and Virginia.
In Europe, they winter around the British Isles (particularly in Scotland and Northern Ireland), the Baltic Sea, and other coastal regions.
Elevation Range
Sea level to 1,000 meters
Climate zones
Temperate, Subarctic
Distribution Map
This map gives you a rough idea of where you might spot a Greater Scaup. The coloured areas show countries where these birds have been seen.
A few things to keep in mind:
- Birds might not be everywhere in the coloured areas, for example, they may be present around the coast of that country
- Where birds live can change with seasons and available food
- This map is quite simple - it doesn't show exact locations
We're working on making our maps even better! Soon, we hope to show you:
- More detailed maps for bigger countries, including state and region
- How birds move around during different seasons
Distribution by Region
Behaviour and Ecology
Bird Attributes
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Share your thoughtsBird Attributes Explained
Our bird attributes system rates various aspects of a bird's capabilities on a scale of 0-100, based on data from field observations, scientific studies, and expert knowledge.
Attribute Categories:
- Agility: Manoeuvrability, speed, and grace in flight or movement.
- Strength: Physical power, often correlating with size and hunting abilities.
- Adaptability: Ability to thrive in various environments or changing conditions.
- Aggressiveness: Territorial behaviour and assertiveness, particularly during breeding seasons.
- Endurance: Stamina, often seen in migration patterns or foraging behaviours.
Understanding the Ratings:
- 0-20: Very Low
- 21-40: Low
- 41-60: Average
- 61-80: High
- 81-100: Very High
Remember, these attributes are relative to other bird species and don't necessarily indicate superiority.
Hover over the icon next to each attribute for more information.
Tap the icon next to each attribute for more information.
Agility
Reflects the bird's manoeuvrability, speed, and grace in flight or movement.
The Greater Scaup demonstrates impressive agility, particularly in water. Their ability to dive to depths of up to 6 metres and manoeuvre underwater to forage for food indicates high aquatic agility. Their whistling wings in flight also suggest considerable aerial dexterity.
Strength
Indicates the bird's physical power, often correlating with size and hunting abilities.
While not exceptionally strong for their size, Greater Scaups possess sufficient strength to dive repeatedly and withstand cold waters. Their medium build (726-1360g) and ability to migrate long distances indicate a respectable level of strength.
Adaptability
Represents the bird's ability to thrive in various environments or changing conditions.
Greater Scaups show notable adaptability, thriving in various aquatic environments from sea level to 1000 metres elevation. Their ability to switch between freshwater and marine habitats, and to adjust their diet based on availability, demonstrates good adaptability.
Aggressiveness
Measures the bird's territorial behaviour and assertiveness, particularly during breeding seasons.
Greater Scaups are not particularly aggressive birds. They are highly social, often forming large flocks, which suggests a relatively peaceful nature. However, males may display some aggression during courtship and breeding seasons.
Endurance
Reflects the bird's stamina, often seen in migration patterns or foraging behaviours.
The Greater Scaup exhibits remarkable endurance. As long-distance migrants capable of sustained flight and frequent diving (submerging for 20-30 seconds at a time), they demonstrate exceptional cardiovascular fitness. Their ability to withstand harsh arctic breeding grounds and cold waters further supports their high endurance rating.
Diet
Greater Scaups primarily feed on mollusks, aquatic insects, and small crustaceans. They dive to the bottom of water bodies to forage, using their broad bills to sift through sediment.
In summer, scaups eat more plant matter in their freshwater breeding habitats, including pondweed, wild celery, sedges, and grasses.
Feeding continues nocturnally as well as during daylight, with tidal patterns influencing feeding times.
Behaviour
Greater Scaups are highly social, often forming large flocks on open water. They are excellent divers, plunging to depths of up to 6 meters to forage for food. During courtship, males perform elaborate head-throwing displays and whistle to attract females.
Vocalisation
Greater Scaups are generally quiet outside the breeding season. Vocalizations are usually limited to a croaking, hoarse series of notes that make a 'scaup' sound, which gives the species its name.
During courtship, males produce a soft, whistling 'whew-whew' call. Females have a hoarse, grating 'arrr-arrr-arrr' vocalization. In flight, their wings produce a distinctive whistling sound.
Nesting & Breeding
Greater Scaups form pairs during late winter and spring migration. They breed in tundra and boreal forest regions, typically near large bodies of water. Females select nest sites on the ground, often on small islands or near water edges.
Nests are shallow depressions lined with grass and down. Females lay 8-9 olive-buff colored eggs. Incubation lasts about 24-28 days and is performed solely by the female.
Ducklings are precocial, leaving the nest within 24 hours of hatching. They can dive and feed themselves immediately but remain with the female for protection for 6-8 weeks until fledging.
Conservation and Status
Global Conservation Status
While currently listed as Least Concern, Greater Scaup populations have shown declines in some regions. Threats include habitat loss, pollution in wintering areas, and climate change affecting breeding grounds. Conservation efforts focus on protecting key wetland habitats and monitoring population trends.
Birdwatching Tips
- Look for large flocks on coastal bays and large lakes
- Observe diving behavior - they submerge for 20-30 seconds at a time
- Listen for the distinctive whistling call of males during the breeding season
- In North America, check for white wing patches to distinguish from Lesser Scaup
Additional Information
Quick Facts
Predators
Did You Know?
- Greater Scaups can dive to depths of up to 6 meters in search of food.
- They are one of the most numerous and widespread diving ducks in the Northern Hemisphere.
- Their name 'scaup' is thought to come from the Scottish word for mussel beds, where these ducks often feed.
References
- 1
website: BirdLife International. 2018. Aythya marila. The IUCN Red List of Threatened Species 2018: e.T22680398A132525108.
View source - 2 3
report, 2016: Wetlands International
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