And all of a sudden they have arrived: Iceland Gulls Larus glaucoides in the Netherlands! With 2 individuals reported in Amsterdam today (a first-calendar year and a second-calendar year), while a second-calendar year showed up at my local gull patch at Katwijk aan Zee, the Netherlands, while we were reading rings.
Rob H. picked it out of the group which consisted mainly of Herring Gulls and Black-headed Gulls, together with a handful of Common, Great Black-backed, Yellow-legged and Caspian Gulls of various ages and a lingering adult Lesser Black-backed Gull (all the others seem to have finally moved south).
It spent about an hour preening, sleeping and more preening, long enough for some local bird watchers to join us and admire this nice looking bird.
Hopefully the Glaucous Gulls will follow soon as well!