Common Black-headed Gull (Larus ridibundus)

Adult Plumages

There are two recognized subspecies of Common Black-headed Gull:

Larus ridibundus ridibundus - Europe (Breeds throughout western Europe and Central Asia from Iceland to northern Mongolia. Winters south to west Africa, Persian Gulf, northern India, SE Asia and eastern China).

Larus ridibundus sibiricus - Asia (Breeds in northeastern Siberia from the Kolyma Dleta to the Kamchatka Peninsula. Winters south to Sakhalin, Japan, Korea, Taiwan and coastal China including Hong Kong).

Subspecific differences are slight. Siberian birds tend to be slightly larger, especially the bill (Dwight, 1925). Dwight also suggests that the black on the primaries may be more extensive in both juvenal and adult plumages. Obviously, more research is needed. Both subspecies are known to occur in North America. Several Alaskan specimens correspond to sibiricus, while birds in the northeast (Maritimes and New England) are likely to be nominate ridibundus, perhaps originating in Iceland. The origins of birds recorded along the Pacific coast (e.g. California) or in central states and provinces is less clear and could easily include both subspecies? Don Roberson for example has pointed out that a number of the Common Black-headed Gulls observed on the west coast have been seen in Bonaparte's Gull flocks that also contain Little Gulls, suggesting the birds have crossed the continent (Roberson, 1980).


Adult Larus ridibundus ridibundus in basic-plumage. Castle Douglas, Dumfries and Galloway, Scotland in December. Photograph copyright of Angus Wilson©.


Adult Larus ridibundus ridibundus in basic-plumage. Castle Douglas, Dumfries and Galloway, Scotland in December. Photograph copyright of Angus Wilson©.


Adult Larus ridibundus ridibundus in basic-plumage. London, England in December. Notice the metal band on the right leg. A large fraction of the Common Black-headed Gulls that winter in central London are banding in the Russian Baltic region. Photograph copyright of Angus Wilson©.


Adult Larus ridibundus ridibundus in transition from basic to alternate plumage. London, England in December. Photograph copyright of Angus Wilson©.


Adult Larus ridibundus sibiricus in basic-plumage. Honshu, Japan in January. Photograph copyright of Angus Wilson©.

Additional pictures of first-winters can be found here.
 

Literature

Dwight, J. (1925) The Gulls (Laridae) of the World; their plumages, moults, variations, relationships and distribution. Bulletin American Museum of Natural History. Vol 52: p63-408.

Grant, P.J. (1986) Gulls: A guide to identification. 2nd edition. Academic Press.

Roberson, D. (1980) Rare Birds of the West Coast. Woodcock Publications.



Copyright © 1999 All rights reserved Angus Wilson
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