I was surprised by the pink blush visible on this bird's plumage. It is apparently caused by oil from the preen gland and may be related to diet. It is most often seen in bird's first arriving on the breeding grounds, but fades quickly.
This species was described by Joseph Sabine in 1818. It is normally improper to name a species after yourself, but in this case, Joseph Sabine claimed he was naming it after his brother, Sir. Edward Sabine who provided the first specimen. Both apparently pronounced the family name "SAB-in." The only member of its genus, the name Xema apparently has no other meaning. Species sometimes included in the genus Larus.
A long-distance migrant with the entire population wintering in the tropics and subtropics. Geographic variation slight and species usually considered monotypic (BNA, IOC, H&M4). The population breeding in the Russian Far-East to Alaska sometimes (e.g. Clements/eBird, HBW) recognized as the large, dark subspecies X. s. woznesenskii. Canon PowerShot SX50 HS.
References:
Burger, J., Gochfeld, M. & Garcia, E.F.J. (2017). Sabine’s Gull (Xema sabini). 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/54008 on 11 July 2017).
Day, Robert H., Iain J. Stenhouse and H. Grant Gilchrist.(2001).Sabine's Gull (Xema sabini), 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/sabgul