Adult Caspian Gulls from the Caspian

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Chris Gibbins
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Joined:Tue Nov 02, 2010 5:15 pm
Adult Caspian Gulls from the Caspian

Post by Chris Gibbins » Wed Aug 01, 2012 7:55 am

Hi everyone.

Im just back from a wonderful trip with Hannu Koskinen and Visa Rauste to Azerbaijan. We were interested in collecting images of the local breeding 'eastern' Caspian Gulls. I've just uploaded images of a sample of adult birds onto my blog. I hope you find them interesting and a useful resource. Plenty to learn and plenty to talk about.....

They are at

http://chrisgibbins-gullsbirds.blogspot.co.uk/


Cheers,

Chris

lou bertalan
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Joined:Tue Nov 03, 2009 2:43 pm
Location:stuttgart, SW germany
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Re: Adult Caspian Gulls from the Caspian

Post by lou bertalan » Fri Aug 03, 2012 7:56 am

hi chris,

again, great job in taking so many reference pics!
surprisingly, i find that their variability matches somehow that of western (ponticus) birds. i would have expected a clearer difference. surely it would be good to do some statistics about features like solid p10 subterminal marks, p4 marks, short p10 tongues and bright yellow legs. these might be more frequent in the caspian sea than in black sea but, from what i've seen and photogr. in the past years in romania, all of these are found among the danube delta population too. the ones with lots of black (solid p10 marks, short and weird shaped p10 tongues etc.) always presented sort of a puzzle - are these "eastern genes", are they just normal variants of pure cachinnans or are they just younger adults (5cy-6cy) that might change when getting older?
to me, the last bird which you compared with an extreme micha from romania, has a more cachi-shaped p10 tongue than that of the YLG - its distal edge ending more or less rectangular towards the inner edge of the feather while in micha it usually reaches the inner edge in a less than 90% angle.

all the best,

lou

Chris Gibbins
Posts:20
Joined:Tue Nov 02, 2010 5:15 pm

Re: Adult Caspian Gulls from the Caspian

Post by Chris Gibbins » Fri Aug 03, 2012 11:34 am

Hi Lou et al.

Yes, Ithink you have hit the mail on the head: with such variability in these eastern birds, all from a single place in the breeding season, along with the variation you mention for western birds, suggests a hard task for anyone trying to find differences between populations that would be useful in the field. A point Visa made during the trip is relevant here - perhaps we should not be to surprised at such variability - we see it in our local breeding Herring Gulls after all. I've thought of trying a few things on birds from Azer, to compare them to western ones, but need to find the energy to code individuals then do the analysis. Hopefully in time...

Glad you found the pics interesting,

Chris

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