black-tailed gull Larus crassirostris
46 cm
Four-year gull distinguished by its black (or black-banded) tail. Breeds from the Russian coast of the Sea of Japan to Japan, Korea, Shandong, and Fujian. On migration and in winter can be found along the length of the Chinese coast, including Taiwan, but is scarcer in the south and more abundant in the north. Rarely reported inland. Breeds colonially on rocky islets and sea cliffs. Narrow-winged and a graceful flyer. Monotypic. Breeding adult has dark, slate-grey upperparts, black primaries tipped white, and white tertial crescents. Rounded head and underparts white. Otherwise white tail has broad black subterminal band, sharply defined, easily seen in flight, and unique among adult gulls in China. Slender bill yellow, with black subterminal band and bright red tip. Legs short, yellow; eyes yellow. Non-breeding adult has dark streaks on crown and nape; may appear hooded. Juvenile brown with heavy scaling above, a pale face, white eye crescents, a completely black tail (no white terminal bar), and a pink bill with a black tip; feet pink, eyes black. First-winter birds paler than juvenile on mantle and scapulars; face paler. Second-winter birds have grey mantle, scapulars, and median coverts and a yellow bill tipped black; there is more white on the tail, as the white terminal bar has appeared, and the black on the tail is beginning to narrow into a bar. Plaintive, cat-like mewing. — Craig Brelsford
ACKNOWLEDGEMENTS
Daniel Bengtsson served as chief ornithological consultant for Craig Brelsford’s Photographic Field Guide to the Birds of China, from which this species description is drawn.
