Birds of Mongolia

ID Adult most likely to be confused with Black-headed Gull, but readily distinguished by sooty-black (not chocolate brown) hood (in breeding plumage); heavier build; thicker, blunter bill; and in flight by distinctive wing-tip pattern. On ground, birds look small-headed with disproportionately bulky body. Adult winter, juv and subadult plumages resemble Mew Gull but head and bill shape are distinctive and Relict never shows tan streaking and barring of imm and winter Mew Gulls. Voice Chuckling ka-ka-ka-kee-a. Habitat Large lakes; also occurs in steppe on migration. Behaviour Nests colonially, mainly on lake islands where it is extremely sensitive to water levels relative to its nesting sites and vegetation cover, resulting in limited breeding success in many years. Status Rare and local breeding visitor to fresh and saline lakes in Great Lakes Depression, the Valley of the Lakes and Lake Tari (formerly Lake Tooroi), Dornod province, and uncommon passage migrant to many localities across Mongolia, late April to early September. Many migrant birds are presumed to be non-breeding wanderers unable to find suitable nesting conditions. Conservation One of the world’s rarest gulls, recognised as a distinct species only in 1970. Nests only on desert lakes in Mongolia, Kazakhstan and China, and winters mainly in coastal China and Korea. Population declining. Considered Vulnerable globally. Listed as Threatened in the Mongolian Red Book (2013). Taxonomy Formerly placed in genus Larus.

ID Most common ‘hooded’ gull in Mongolia. In breeding plumage, readily distinguished from other regularly occurring dark-headed gulls (despite its name!) by its chocolate brown head and white leading edge to wings. For comparisons with rarer gull species see Relict, Brown-headed, Slender-billed and Little Gulls. Voice Harsh drawn-out skreeer and sharper kek calls. Habitat Nests in reedbeds and other dense vegetation on lake and river shores and visits other aquatic habitats, including arid steppe and desert lakes on migration. Behaviour Nests in dense colonies. In addition to foraging in and near water, frequently forages for insects in flocks in steppe and agricultural land. Status Common breeding visitor across Mongolia and fairly common passage migrant, late April to late August (early September in the Gobi). Taxonomy Formerly placed in genus Larus. [Alt: Common Black-headed Gull]

ID In all plumages most closely resembles Black-headed and Brown-headed Gulls, but readily distinguished in breeding plumage by completely white head and pale iris; otherwise best told by its distinctly slender neck, head and bill and by faint (vs. dark) ear-spot of imm. Voice Calls similar to Black-headed Gull but more rasping. Habitat Lakes and other aquatic habitats. Behaviour Gregarious; flocks with other gull species. Status Vagrant. A single record at Lake Uvs, Uvs province, 19 June 1977. Taxonomy Formerly placed in genus Larus.

ID Breeding adult very similar to Black-headed Gull, but slightly larger. In breeding plumage the head is paler shade of brown, especially around the bill, and iris is pale yellow, not dark. In all plumages has longer, heavier bill and broader, more rounded wings, with much more black in wing-tips than Black-headed. First-winter resembles non-breeding adult, but distinguished by dark brown wing-coverts and dull orange legs and bill. Compare also Slender-billed Gull. Voice Similar to Black-headed Gull but lower-pitched. Habitat In Mongolia, brackish lakes. Behaviour Similar to Black-headed Gull. Status Vagrant. A 2nd-year bird at Lake Bööntsagaan, Bayankhongor province, 7 June 2004 and three at western shore of Lake Uvs, Uvs province, 5 July 2004. Taxonomy Formerly placed in genus Larus.

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GULLS II

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