Hey Tweets,

I posted a Glaucous Gull sighting on the 10th from the mouth of the Cedar River, but am pulling that identification. At the time, the only confusion species I considered was a hybrid Glaucous x Glaucous-winged, and the pale iris made that easy to rule out. Looking on eBird, the sightings of adult Glaucous Gulls were pretty infrequent, so I was poking around looking for anything else, and came across this:

https://www.allaboutbirds.org/guide/Glaucous_Gull/species-compare/39522551
[https://www.allaboutbirds.org/guide/assets/og/75239011-1200px.jpg]<https://www.allaboutbirds.org/guide/Glaucous_Gull/species-compare/39522551>
Glaucous Gull Similar Species to, All About Birds, Cornell Lab of Ornithology<https://www.allaboutbirds.org/guide/Glaucous_Gull/species-compare/39522551>
Similar looking birds to Glaucous Gull: Glaucous-winged Gull Nonbreeding adult, Glaucous-winged Gull First winter, Iceland Gull Adult (Iceland), Iceland Gull Nonbreeding adult (Thayer's), Iceland Gull First winter (Iceland), Herring Gull Nonbreeding adult (American)
www.allaboutbirds.org

Iceland Gull (Iceland) was not something I had considered at the time, and is an even more disastrous ID (insomuch as there aren't any sightings of these guys in the state). That said I can speak to the 3 or 4 features that would help with the ID. I am running off of this image, and any other crumbs I could find off of the Internet, and about 10-15 minutes of scope views of the gull at 150-200 feet in excellent lighting.

Mantle: I was looking at how pale the mantle was, in trying to rule out Glaucous x Glaucous-winged. My Sibley's said that the mantle would be slightly darker in a hybrid than in a pure Glaucous Gull, and my thought was "How can what I'm looking at be darker than anything?" It wasn't white, but such a pale pale grey. The images show the lighter mantle of the Iceland (Iceland) almost melting into the white around it, and that fit the impression I got from the bird. The Internet gave me a range for Glaucous Gull - usually slightly darker, and usually a better delineation of the mantle, but not always.

Bill: Those bills both have the red spot I noted. I did not note the color in the sighting, but the Glaucous appears to have a pretty heavy bill that tends a little towards school bus orange/yellow. This wasn't true of all of the images I found for the species (color wise), but my impression overall was that the bill seemed fairly "normal" and also has me leaning towards Iceland (Iceland).

Facial expression: The sum of the iris, head shape, orbital - seems to add up to a friendlier expression on Iceland (Iceland), something that seems helpful when sorting Thayer's and Herring. This bird did not seem angry.

Size: Would have helped . . . but it was in the water, and was not something I was looking for.

I hope it shows up again, and someone gets a picture. Gulls are, for me, a mess. There are so many hybrids running around, and subtle differences to sort one out from the other. They are usually more frustrating than enjoyable. Look closely at a gull. . . ? Why would I do that, and ruin a perfectly fine day of birding?? But this one was striking, whatever it was. With any luck, someone more pay-attentiocal than I will have a go at IDing it, although there were a few eBird lists from the mouth yesterday that didn't turn it up.

Cheers,

Tim Brennan
Renton
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