glaucous-thing gull

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: It is a funky looking, confusing bird, but I think probably pretty typical of small-end barrovianus with some Glaucous-winged genes showing. I would age it as 1st-basic based on the look of the remnant covert checkering. The pale tertials with dark tip markings would seem to rule out a faded GW or leucistic Herring or other. : The appearance of the tertials, amount of clean pale in the bill, and the definition of the eye arcs suggests to me that this IS at least part, if not mostly Glaucous. However, the amount, shape, and lack of definition to the edges of the black in the bill is outside the range of pure Glaucous in my opinion. In my experience birds that show this kind of 'near but not quite' Glaucous look to the bill also often tend to show or border on showing other un-Glaucous-ish traits. This happens enough where I think a bill pattern like this - with the black reaching this far in along the lower cutting edge, and also being so diffusely bordered on both ends, is a pretty good first clue that you're dealing with a not-quite-pure Glaucous. I'm not sure anyone knows exactly where to draw the line between pure and not pure, but I think this bird at least is clearly over it. Also, the pale portion of the bill doesn't seem quite clean, showing a bit of duskiness on the upper mandible, which a pure Glaucous probably shouldn't show. : In the case of this bird the other un-Glaucous-like features besides the bill might be the overall shape, and perhaps the fact that the covert markings still have some pretty good definition and seem a bit dense and GW-like. Glaucous are variable in this respect, but I think most 1st-basic Glaucous would be closer to pure white at this date and stage of fading, or at least would have remnant covert markings spaced a bit more sparsely. I think typical Glaucous also average not quite so dusky on the belly, although this is also variable. : At first glance at the one swimming photo the forehead seems steep and the eye quite proportionately large, suggesting an Iceland/Thayer's type, but I think that is partially due to the angle of view. In the other photos the forehead seems more flattish and GW-like. The bill also seems proportionately too thick and long for Iceland, perhaps even extreme large-end : for a Thayer's, and seems proportionately typical of barrovianus to me. The bird also seems too thick-necked, thick-legged, barrel-chested, large-bodied, and a bit chunky in the rear for an Iceland/Thayer's type. The overall shape and proportions do seem a bit funky for Glaucous, including barrovianus, although it might take some thought to pin down exactly why. I do think a good explanation would be that this bird is intermediate in shape between typical (smaller) barrovianus and GW. The bird seems smallish, long-winged, and a bit large-eyed for GW (more like a small barrovianus), but seems to have body/head proportions and head shape closer to GW than anything else. Adding all this up I'd feel reasonably confident betting on Glaucous (barrovianus) x GW. : Cheers, : Phil Pickering : Lincoln City, Oregon

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