Last Sunday morning (3/12) at the rendering plant in Tacoma, off of Lincoln Avenue, I spent some time studying and photographing gulls. I've spent a lot of time the last 3 winters studying gulls, particularly the Thayer's gull, and last Sunday was the first time I've seen the full range of variation in first winter plumage in this species in one place at the same time. They ranged from being dark and very similar to first winter herring gulls, to one very pale individual that I thought was an Iceland gull, and everything in between.
Although the potential Iceland gull was very pale, I realized that it didn't have any more white in the plumage than does a Thayer's gull; it was pale because the brown ground color of the plumage was a very light brown, almost buffy brown. The bird appeared darker in flight, with darker brown wingtips and a distinct secondary bar. The pattern of the tertials (cited as a good field mark to separate Iceland and Thayer's ) in this individual was more typical of Thayer's. However, several Thayer's gulls had all the classic field marks of Thayer's, except they had the tertial pattern of Iceland!
I've been down there a number of times this winter, and on Sunday I definitely saw individual Thayer's gulls that I had not previously observed this winter. While there are large numbers of Thayer's gulls in the area, and I don't expect to see EVERY Thayer's gull that winters there, I think the observation of so many plumages that I haven't seen yet suggests that many of these are gulls that wintered somewhere else and are in migration.
Note that of the 7 records of Iceland gulls (listed below) that the WBRC has accepted through their fourth report (which will be published in the next issue of Washington Birds), 4 of them are from March and April; all are of first winter birds. So even though the days are getting longer, trees are blooming, and birds are starting to sing, it's still not too late for a "winter" bird like an Iceland gull to show up.
These are the dates of accepted records of Iceland gull for Washington State. (This doesn't include any records under review, such as the adult in late January 2000 in Tacoma.)

25 November
7 December
8 January
17 March
20 March
6 April
16 April


Mike Donahue
Seattle