Common Gull Larus canus canus & L.c. heinei

(last update: March 12, 2012)

Common Gull (Larus canus) adult April - August

Common Gull is a widespread species on the northern hemisphere with several sub-species: in N America brachyrhynchus, in W Europe nominate canus, in W Asia and Russia heinei and in the Far East sub-species kamtschatschensis.
The American race brachyrhynchus is a breeding bird of Alaska, the American West coast and inland Canada. After the breeding season, it disperses south along the coast to California. Brachyrhynchus can be readily told from nominate canus, and therefore sometimes considered a full species: Mew Gull. The differences can be found in the bill (in some birds obviously small), but most in plumage.
Nominate canus is a common breeding bird in North Europe, wintering both in the breeding area and slightly south, to the northern coast of the Mediterranean. 
The race heinei breeds from White Russia eastwards to central Mongolia, in a broad band over the tundra region of inland U.S.S.R. It can be found wintering in the central Asian states, southern Black Sea and Caspian Sea and further south to the Persian Gulf. Part of the eastern population of heinei may follow a more eastern route to the coast of China. Heinei is slightly darker than the other three sub-species. 
Race kamtschatschensis breeds in eastern Siberia and, as the name indicates, Kamtschatcha. In winter it moves southwards along the coast, wintering in Japan, the Korea's and China. It is the largest race, almost as large as Herring Gull. Adult kamtschatschensis is slightly darker than canus and brachyrhynchus, but still paler than the central Russian race heinei. The description below largely follows from P.J. Grant: "Gulls, a guide to identification".

ADULT COMMON GULL

Common Gull has a partial moult in spring. It starts in February and is completed by April, leaving birds in so-called "adult summer" plumage. The head turns white, with a red orbital ring. The bill turns all yellow or yellowish-green. In summer, head, neck, tail and under-parts are completely white. The upper-parts are medium grey. The outer primaries are black with large white tips. The inner primaries and secondaries are pale grey with a white tip, creating a white trailing edge. The white crescents on the tertials are very broad.
Adult brachyrhychus normally have a black sub-terminal band on P5-P10. Between this black band and the grey centre, a large white spot is visible both from above and below on P5-P7, creating a string of pearls on these primaries. P9 and P10 show large white mirrors.

Measurements in mm's:
wing canus: 320-385 (Dwight), 321-380 (Birds of West. Paleartic III),
tail: 124-148, bill: 30-38,
tarsus: 48-58; n = 16 (Dwight, 1925); 
wing heinei: 351-395 (BWP III); 
wing brachyrhynchus: 328-366 (Dwight 1925);
wing kamtschatschensis: 365-412 (BWP III).