Two possible hybrid gulls

in Massachusetts - July 2008

created by Blair Nikula

Both of the two 1st-summer (2cy) gulls depicted below I initially thought were Lesser Black-backed Gulls. At first glance, the dark, chocolate-brown mantles, contrasting with mostly whitish head and body were suggestive of that species.  Closer examination, however, revealed characters that are inconsistent with that species in that plumage. Both birds seem like good candidates for Lesser Black-backed x Herring gull hybrids.

North Monomoy, Chatham, Massachusetts - 26 July 2008:
This bird was sleeping when I first noticed it among a flock of 150+ gulls (including 3 Lesser Black-backeds).  When it awoke, I was struck by the paleness of the bill, which is not typical for LBBG in its first summer, nor are the pale inner primaries.
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Stellwagen Bank, off Provincetown, Massachusetts - 27 July 2008:
I thought this bird was a typical 1st-summer LBBG, until it flew, revealing an unusually dark upper tail, contrasting little with the dark terminal band.  There is also quite a bit of paleness in the base of the bill, though this may not be too unusual at this date. Additionally, the bird is quite husky, with a pretty thick bill and shows a pale wedge on the inner primaries.
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