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Hi everybody,

I would like to know your opinion about a 4 cy Caspian I observed yesterday in Switzerland. This bird has a green ring (unread but probably from Poland) on the right leg.

http://www.pbase.com/stephaubry/image/130068712

http://www.pbase.com/stephaubry/image/130068727
Do you think it's a pure cachinnans ?

Many thanks for your comments

Stéphane

hello stéphane,

i see a 'very pure' cachinnans, probably 4cy as you labelled it, with large apical spots and just a few ink streaks on primary coverts but can a 3rd cycle totally be excluded? nothing suggesting any other species involvement - what is it that bothered you?

lou

Hi Stéphane!

If you by the head streaking (probable Herring influence not clean unmarked except for the neck), bill colour and primary pattern question you gull as a 100% Caspian, I would say that it looks alright for a 4cy type (female?), on all these accounts, give and take some for the "dirty" looking head perhaps.

http://www.pbase.com/slisch/image/105893599

Some in this age class has more black markings on the primary coverts, some less, like your bird, while some have a larger mirror on p9 and many a duller bill clour - especially at the inner parts of the bill. On structure and other features it looks like a good Caspian to me.

JanJ

caspian gull doesn't "need" an all white head in winter, not even as an adult, a more or less fine striation can be present everywhere on head but the forehead, usually very fine and bleached out soon after complete moult but some have it through mid winter. a younger bird like this is even more likely to show a denser striation.

Hi Jan and Lou,

Many thanks to your replies.

My doubt was about the primary pattern (especially P10-9), not absolutly typical to my eyes (probably due to the age of this bird).

All the very best and good gulling !

Stéphane

a similar bird in terms of primary pattern large p10 mirror with subterminal band, small p9 mirror (but seemingly only on left wing!), long p10 tongue, large apical spots, little dark markings on primary coverts - uncertain if a 3rd or 4th cycle: http://lou.bertalan.de/gulls/pic/hi/up_0432.jpg
as i said some 3rd winters (3rd cycle, with 3rd generation primaries) can have pretty large white primary tips already.

cheers to swizzerland

Many thanks Lou,

Very nice and interesting picture !

Cheers

Stéphane

When judging the far wing, I see a 3rd winter cach!

Theo

Stéphane wrote:Many thanks Lou,

Very nice and interesting picture !

Cheers

Stéphane

I agree with Stéphane - a very nice pic!