Larus glaucoides
All white wingtips like Glaucous Gull. Told apart from latter by rounded head, longer wings and shorter, more slender bill. Bill shorter than half the length of head, and lacks prominent hook. Primaries extends well past tail in sitting birds, and the whole rear of the bird seem slimmer. Eye bigger than in Glaucous Gull, with a more "gentle" expression. Comparison with nearby Herring Gulls fruitful. Iceland Gull often smaller than Herring Gull, and less heavy, while Glaucous Gull usually larger. Impression reinforced by Iceland's agile maneuvering.
Like Herring Gull, but tone sharper.
Wikipedia: map (se also Xeno-canto below)
Birdlife ecology
