- Aythya marila
Identification
A medium sized diving duck, slightly smaller than the pochard but larger than tufted duck.
Male easily identified by the rounded head which is a glossy green-black and lacks a tuft. The eye is yellow and the bill pale grey with small black ‘nail’. Lower throat and upper chest area black, as is the rump and vent area. Flanks and belly white with fine vermiculations on the back, these appearing greyish white at long range.
Eclipse Male appears browner than the breeding bird, and it can have a pale patch to the base of the bill. The white flanks take on a muddied appearance.
Female is much harder to identify. The head shape is rounded, yellow eye and with a white area at the base of the bill which can be quite large. In spring and summer most birds have a pale area on the ear-coverts. The overall colouring is a dull brown with slightly paler flanks. At very close range the vermiculations on the back of the female can be made out.
Similar Species
Tufted Duck, Lesser Scaup and Common Pochard. The Lesser Scaup is essentially identical in all plumages, but the head shape is slightly different, with a peak behind the eye instead of on the forehead. The bill in the Greater is also longer and wider. These differences can be quite difficult to discern, so range and habitat are often better determinates.
Distribution
North America from roughly the U.S. - Mexican border northward along the coasts in winter. Migrates into the Territories of Canada and into Alaska in summer.
Also found in Northern Europe and Asia.
Taxonomy
Two subspecies recognized:
- A. m. marila breeds in northern Eurasia; winters to the Mediterranean region, India, Japan, Korea, and China
- A. m. nearctica breeds northern North America; winters south to the southern United States and northwestern Mexico
Habitat
Prefers salt water along the coast in winter. In summer can be found on ponds and lakes throughout the lower 48 states of the U.S., Canada, and Alaska.
Behaviour
Diet
Omnivorous; their main diet consists of molluscs.
Vocalisation
<flashmp3>Aythya marila (song).mp3</flashmp3>
Listen in an external program
References
- Clements, J. F., T. S. Schulenberg, M. J. Iliff, D. Roberson, T. A. Fredericks, B. L. Sullivan, and C. L. Wood. 2014. The eBird/Clements checklist of birds of the world: Version 6.9., with updates to August 2014. Downloaded from http://www.birds.cornell.edu/clementschecklist/download/
- Gill, F and D Donsker (Eds). 2014. IOC World Bird Names (version 4.3). Available at http://www.worldbirdnames.org/.
- Handbook of the Birds of the World Alive (retrieved September 2014)
Recommended Citation
- BirdForum Opus contributors. (2024) Greater Scaup. In: BirdForum, the forum for wild birds and birding. Retrieved 7 May 2024 from https://www.birdforum.net/opus/Greater_Scaup
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