The population breeding in the Russian Far East and Bering Sea region is L. a. vegae characterized by darker
back, and orange-red orbital ring compared with typical smithsonianus of North America. Adult vegae
also have smoky gray underside to primaries and white tongue tips on P6-P7. Eye color is variable, but usually
dark. These were very common on our visit to Choshi and we called them "Vega Gulls" for convenience regardless
of their species status. Immatures were quite variable. We speculated that some very dark birds which appear to
have retained juvenile plumage into February had delayed their molt. However I remain uncertain how to distinguish
those birds from first cycle "Taimyr Gulls," a taxon of unclear status but possibly a hybrid zone between
Heuglin's Gull and Vega Gull and sometimes treated as a race of Lesser Black-backed Gull.
Taxonomy is complex and unsettled. AOU and Clements/eBird retain a traditional arrangement of one species of Herring
Gull. H&M4 and HBW split North American populations as a separate species, American or Arctic Herring Gull
(L. smithsonianus). IOC further splits Vega/Siberian Gull (L. vegae) including Mongolian Gull citing
Collinson et al. 2008, Yésou (Dutch Birding 24:271-298, 2002). Brazil (2009) further splits Mongolian Gull
from Vega. Canon PowerShot SX60.
References:
Brazil, M. (2009). Birds of East Asia. Princeton Univ. Press.
Collinson, J.M., Parkin, D.T., Knox, A.G., Sangster, G. & Svensson, L. (2008) Species boundaries in the Herring
and Lesser Black-backed Gull complex. Brit. Birds 101(7): 340–363.
del Hoyo, J., Collar, N. & Kirwan, G.M. (2017). Arctic Herring Gull (Larus smithsonianus). In: del Hoyo, J.,
Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.). Handbook of the Birds of the World Alive.
Lynx Edicions, Barcelona. (retrieved from http://www.hbw.com/node/467313
on 2 July 2017).
Howell, S.N.G. & Dunn, J.L. (2007) Gulls of the Americas. Houghton Mifflin, Boston.
Malling Olsen, K. & Larsson, H. (2003) Gulls of Europe, Asia and North America. Christopher Helm, London.
Nisbet, Ian C., D. V. Weseloh, Craig E. Hebert, Mark L. Mallory, Alan F. Poole, Julie C. Ellis, Peter Pyle and
Michael A. Patten.(2017).Herring Gull (Larus argentatus), The Birds of North America (P. G. Rodewald, Ed.).
Ithaca: Cornell Lab of Ornithology; Retrieved from the Birds of North America: https://birdsna.org/Species-Account/bna/species/hergul