'Taimyr Gull' Larus heuglini 'taimyrensis' that is generally regarded as a hybrid population between Vega Gull L. vegae and Heuglin's Gull  L. heuglini is rather easily found among Vega Gulls in Japan. On the other hand Heuglin's Gull L. heuglini heuglini is much scarcer. And identifications often can be problematic when a individual appears like both dark 'Taimyr Gull' and pale Heuglin's Gull. In both forms, molt is later than in Vega Gulls about a month or more, generally finishes in Feb-Mar. We are trying to separate heuglini and 'taimyrensis' in recent pages below. But note that some of those judgments are often tentative.