Species Profile
Greater Scaup
Aythya marila
Greater Scaup
Quick Facts
Conservation
LCLeast ConcernLifespan
10–15 years
Length
39–56 cm
Weight
726–1360 g
Wingspan
71–84 cm
Migration
Long-distance Migrant
Also known as: Bluebill, Broadbill
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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.
Identification & Characteristics
Male Colors
- Primary
- Black
- Secondary
- Grey
- Beak
- Blue
- Legs
- Grey
Female Colors
- Primary
- Brown
- Secondary
- White
- Beak
- Grey
- Legs
- Grey
Female Markings
White patch at base of bill
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
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.
Distribution
Where to See This Bird
Explore regional guides for locations where this bird has been recorded.
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.
Calls & Sounds
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
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
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.
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