Views on likely hybrid

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mike temple
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Joined: Mon Feb 16, 2015 8:52 pm

Views on likely hybrid

Post by mike temple » Sun Jan 15, 2017 1:08 pm

I volunteer with a UK gull-ringing group - despite birding for many years I have only in the past couple of years got interested in gulls, and volunteered with the group. Often we trap (cannon net) 'interesting' birds and I am always interested by the diversity of plumage and size even within a species - and also the discussion that ensues after the trapping.

One such case yesterday. See photos below. All agreed most likely a 1w/2cy hybrid Caspian x Herring - possibly a F2 or even F3. If the wing alone was found we felt sure it would be ID'd as Caspian, but the tail/rump and head streaking all point clearly to Herring. The bill is small and thin without much of a gonydeal angle. We did take metrics which I cannot recall, but it was at the smaller end of the range (female?).

Anyway I'd welcome any opinion and observations. As you can see it was colour-ringed (U5ZT) so hopefully it will be seen in future years and we can see what it grows up into!

Best regards

Mick
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marsmuusse
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Joined: Sun Sep 27, 2009 12:43 pm

Re: Views on likely hybrid

Post by marsmuusse » Tue Jan 17, 2017 2:55 pm

I can see why you have thoughts on Caspian, but in general it most looks like Herring Gull to me. Replaced wing-coverts of course is pointing away from Herring.

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