12/12: I'll be out of town for much of the next 5 days (with only intermittent laptop access) but wanted to post these images of this interesting Thayer's-type bird from the Windsor Landfill today. Found the bird at noon, had it in view for ~2 mins before it flew down towards the Farmington River, ran back to the car to jot down notes and a flight sketch (wingtip looked good for Thayer's from both above and below), then searched for two more hours without success.
Images in no particular order:
Left-center. Mantle color was a tad darker than surrounding HEGUs, but by a very slight amount. Decent general comparison to nearby HEGUs.
Dark iris, but when the light hit it just right I could see that it was a touch paler than the jet-black pupil.
Close-ups of wingtip. Primary tips were black (very HEGU-like).
Nice example of the bird's expression. Note the dark eye, forehead sloping into bill with yellow-green base, and soft/blurry streaking through the head onto the nape and breast. Orbital ring in the field was viewed as deep red-pink.
Just for fun, here's a pic of a dark-eyed "Kumlien's" Iceland Gull that was also present:
And a first-winter Glaucous Gull: