Friday, 6 February 2015

That Arctic gull

Iceland Gulls do not hybridise - those words are sacrosanct. Apparently.
presumed hybrid gull, Essex 31st Jan 2015
Last Saturday on the tip, an interesting gull was present. Having already seen a couple of hybrids up there this year, alongside at least three leucistic birds, it's second nature now to be skeptical about any gull identification being straightforward. And though there was a lot of conversation at the time about it being a Kumlien's Gull, its pale iris combined with its retarded plumage always made me feel very uneasy.
presumed hybrid gull, Essex 31st Jan 2015
Admittedly, it was a large bird - at least for an Iceland-type Gull. About the same size as your smaller end Herring Gull. With a long primary projection and with a comparatively short, tubby bill there were some elements of its jizz that pointed towards a glaucoides/kumlieni. Possibly. The off white primaries, pale tail and unbarred, hoary underwing-coverts suggested some white-winged gull influence. The breast and underparts were not quite as smooth as you'd expect on an Iceland Gull, suggesting perhaps some Herring Gull influence.

presumed hybrid gull, Essex 31st Jan 2015
So hopefully the few photos of the bird here give you an idea of what it felt like, and there are more (better) photos here too.
presumed hybrid gull, Essex 31st Jan 2015
So, in conclusion, I'd now offer the following: -
- it's probably got some Herring Gull ancestry
- it appears to fit a third calendar year bird, with the pale iris present on this age as well as the plain, moulted scapulars.
- the lean bill and deep pink legs mimic that of an Iceland Gull

Thanks to Rob I, Josh J and Niall K for the subsequent discussion; and of course to Steve A and Dave A who shared the observation. Hopefully it'll still be about this coming Saturday. Any further comments would be appreciated too...

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