These Glaucous
Gulls Larus hyperboreus were photographed in late August and September 2006 at Kotzebue and Barrow, Alaska. They are presumeably of the form barrovianus, but I have my suspicions that some secondary contact with American Herring Gull or possibly Vega Gull or even Thayer's Gull took place in the recent past (genetically speaking) due to the incidence of birds with less-than-textbook wingtip and/or bill patterns. The majority of birds looked typical, but I was surprised at the farly large minority of birds that showed various degerees duskiness in the wingtips:
Note below the orbital ring color of the above adult:
