I have a set of photos showing the Mew Gull with Ring-billed Gulls, including one that makes a good color swatch comparison where the Mew is biting a nasty Ring-billed.
The set of photos is here:
One photo is a montage showing wing specimens compared to the Thomaston bird:
Photo showing Mew biting Ring-billed here (there are others w/ Ring-bill):
Here is a good size comparison (Mew in back but relative size is as not distorted):
The jury is still out on this bird, but it does show several features that are atypical or not shown by any of the Eurasian taxa of Mew Gull. A simplistic way to analyze this bird is that it is clearly a shade darker than Ring-billed Gull and a good deal smaller too. Darker backed Mew Gulls in Eurasia are all larger than the nominate canus of Europe, which is only slightly smaller and darker than Ring-billed Gull. Small and dark suggests those other Eurasian taxa are not involved here, even though some have occurred in North America.
The wing pattern show a long tongue of gray on the second primary from the outside (p9) and another long tongue on the third (p8). That is more like the North American breeding race (see the montage photo for an explanation and comparison).
As for size and bill size, there is a lot of overlap in bill between European birds and North American birds, which average very slighly shorter. But a male North American bird could be longer-billed than a female European bird. Bill depth separates slightly better, but we would need a measurement to determine it.
As I said in my first post about this bird, the time of year is out of sync with other Eurasian Mew Gull records in the Northeast. This had me thinking a North American source was possible even though accidental to the East coast (and I'm not sure any is documented with photos).
An intriguing bird for sure. Kudos to Don Reimer!
Louis Bevier
Fairfield
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