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Greater Scaup

From Opus

A. m. marila, female (left), adult male (centre), and late first-winter male (right)Photo by soenkeBaltic Sea, Schleswig-Holstein, Germany; March 2003
A. m. marila, female (left), adult male (centre), and late first-winter male (right)
Photo by soenke
Baltic Sea, Schleswig-Holstein, Germany; March 2003
Aythya marila

Contents

[edit] Identification

Length 40–50 cm, wingspan 70–80 cm, weight 900–1250 g
A medium sized diving duck, very slightly smaller than Common Pochard (much overlap), but distinctly 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 and first-winter male appear browner than the breeding males, more like females, with a pale patch to the base of the bill. The white flanks take on a muddied appearance.

Female shares the rounded head shape and yellow eye, and with a white area at the base of the bill which can be quite large. In spring and summer most birds also have a pale area on the ear-coverts. The overall colouring is a dull, often slightly rufous-brown with slightly paler flanks. At very close range the vermiculations on the back of the female can be made out.

A. m. nearctica, Photo by PeakXVNew Brunswick, Canada, April 2013
A. m. nearctica,
Photo by PeakXV
New Brunswick, Canada, April 2013

[edit] 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 with a hint of a short stubby crest, a smaller black spot on the bill's 'nail', and in males, coarser vermiculation on the grey mantle. In flight, the white wingbar is only on the secondaries, grey on the primaries. 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.

[edit] Distribution

Holarctic. Breeds across the far north of Europe and Asia (Iceland, and across northern Scandinavia and Russia), and northern North America (Alaska and northern Canada). Migratory, wintering off sheltered sea coasts and on larger freshwater lakes close to the limit of frozen waters; in Europe mostly in Scandinavia but some south to Ireland, Britain, the Alps (Lake Geneva, Bodensee, etc.) and the Black and Caspian Seas; in Asia mainly off the coasts of Japan, Korea, and eastern China; and in North America on the Great Lakes and along coasts south to roughly the USA - Mexico border. Males tend to winter further north than females.

[edit] Taxonomy

Two subspecies are recognised[1][2]:

[edit] Habitat

Prefers salt water along the coast in winter, but also uses larger freshwater lakes. In summer, breeds on tundra lakes and pools.

[edit] Behaviour

[edit] Diet

Omnivorous; their main diet consists of molluscs. In the past, large flocks also gathered to feed on spent grain left after brewing beer and dumped at sea in the Firth of Forth in Scotland, but pollution control measures have stopped this food resource.

[edit] Vocalisation


Listen in an external program

[edit] References

  1. 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/
  2. Gill, F and D Donsker (Eds). 2014. IOC World Bird Names (version 4.3). Available at http://www.worldbirdnames.org/.
  3. Handbook of the Birds of the World Alive (retrieved September 2014)

[edit] External Links


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