This (top) is an immature bird showing the distinct pink-based bill with contrasting black tip. Note also the barring on the tail and wing coverts and the white wing tips. It can be difficult to age immature Glaucous Gulls due to variation in molt and appearance.The light eye suggests that this is a SY (2nd Calendar Year) bird hatched in 2017. Four subspecies usually recognized. By range, this is L. h. leuceretes which breeds across northern Canada to Iceland and winters in North America. It is a large, big-billed subspecies. Adults have a slightly paler mantle than nominate. However some authors merge leuceretes with nominate. The similar but smaller Iceland Gull does not actually breed in Iceland and we did not see that species on our visit. Canon SX50 HS PowerShot
References:
Burger, J., Gochfeld, M. & Garcia, E.F.J. (2018). Glaucous Gull (Larus hyperboreus). 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 https://www.hbw.com/node/53979 on 20 September 2018).
Howell, S.N.G. and Dunn, J. (2007) A Reference Guide to the Gulls of the Americas. Peterson Field Guides, New York.
Malling Olsen, K. & Larsson, H. (2003) Gulls of Europe, Asia and North America. Christopher Helm, London.
Weiser, E. and H. G. Gilchrist (2012). Glaucous Gull (Larus hyperboreus), version 2.0. In The Birds of North America (A. F. Poole, Editor). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bna.573