Heuglin's Gull

Heuglin's gull, or Siberian gull, is a large Larus gull whose rank remains unsettled. Many authorities treat it as Larus fuscus heuglini, a subspecies of the lesser black-backed gull, while others use the full-species name Larus heuglini followed by this guide. Eastern birds can be paler above and have been called Taimyr gulls, although current interpretations often regard them as products of hybridization with Vega gulls (IOC World Bird List; Wikipedia, general account).

Its breeding distribution is centred on northern Siberia, with migration bringing birds south and east through Asia. Identification is difficult because plumage changes with age and season and overlaps with other large white-headed gulls. Mantle shade alone is unreliable, particularly where Vega, lesser black-backed and related gulls occur. Korean records should therefore use a combination of structure, wing pattern, moult and age-specific plumage, ideally with photographs. No unsupported Korean abundance or breeding claim is made here (IOC World Bird List; British Birds).