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Glaucous, hybrid, or ??? gull - eastern Pennsylvania, USA, 12 Feb. (1 Viewer)


Well-known member
United States
Hello all,

I'm posting this for the finder (Jason Hall), who has been asking around for opinions on this gull seen at Green Lane Reservoir, Pennsylvania on 12 February this year.

Birds were sort of distant and he was working with low light, but still managed some photos of this white-winged beast. Several folks have floated the idea of Glaucous-winged Gull, which would be a state first record, but many have also acknowledged that a hybrid is possible. I believe Jason did get a video of the bird preening, which I may be able to post later if that helps.

Can Glaucous Gull show this primary pattern, head shape, and all-dark bill? Or would Glauc x Herring be more likely? Or even the mega-rare Glaucous-winged? All opinions are appreciated on this one. If folks would rather I post individual Macaulay Library media links, I can do that too. The eBird checklist has a few observer comments as well as the photos.


Andrew Whitehouse

Professor of Listening
Staff member
I've never known a Glaucous Gull to show an all dark bill, so I would say that it's not a pure Glaucous. I'm not sure what it is though.

lou salomon

the birdonist
Aren’t the primary tips a bit dark for pure GWG Lou, or are they within variation?

slightly more pigmentation towards outer primary tips is normal. they ghost the adult pattern, in first cycle like in this: http://tgreybirds.com/GlaucouswingedGull35.jpg the OB seems to be a 2nd cycle, though, also sporting those dark tips. don't find a good link at the mo (but down left in the new gull ID guide, on page 165 ;)). or this: https://a4.pbase.com/o4/38/465938/1/91015381.NcnbLhdc.offCypressPt_3780.jpg
Last edited:


Well-known member
Cheers Lou, it’s a few years since I’ve seen them.
I can recall “Olympic” gulls being more numerous than GWG’s, If I get out this year, I’ll endeavour to “shoot a few” frames. 👍


Well-known member
United States
Just an update on this bird. It's been re-found in the next county (Bucks, PA), and the re-finder has gotten phenomenal pictures! Here's Kevin Fox's checklist with photos:

A great bird! It looks quite similar in plumage to the 2nd-winter (now 3cy) bird that spent much of Dec. and Jan. in Ontario, Canada. There are very few, if any, other known Glaucous-winged records on the East coast. A pattern of vagrancy in the Midwest/Great Lakes does seem to be there, though.

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