www.gull-research.org

Bit of a weird looking bird, seen at Blankenberge (Belgium) today. I find it difficult to decide upon its age, but a retarded 3rd-cycle would be my guess.
Photos are not great because the bird was feeding far off at sea.

hi peter,

this one is a bird very similar to yours: http://lou.bertalan.de/gulls/pic/hi/up_0431.jpg and http://lou.bertalan.de/gulls/pic/hi/up_0122.jpg in terms of brown parts distribution and rectrices. i struggled to age it but decided it has to be a 3rd cycle, especially by 3rd gen. looking tail band and inner primaries with wide white tips. and it has a longish p10 mirror. i have never seen a 3rd cycle with such a small p10 mirror(!) like yours and thus immediately reacted: this is a 2cy. some 2cy indeed can show pretty pale greyish inner primaries like e.g. this: http://lou.bertalan.de/gulls/pic/hi/up_0114.jpg - but note black reaching p3 and no clear white tips contrasting to the grey (and typical 2nd gen. rectrices). so, in the end i think you're right with 3rd cycle even though it has an incredibly small p10 mirror since most caspians at this age look like this! : http://lou.bertalan.de/gulls/pic/hi/up_0415.jpg

http://www.netfugl.dk/pictures/birds_us ... 7013_3.jpg this 2nd cycle has pale 4 inner primaries with seemingly white tips! and a pale iris.

all the best,

lou

Peter's bird looks like a 3cy to me too.

Theo

0431 looks a 3cy too, 0415 may also be a 4cy ...

Theo

I agree with the suggestion 3cy. Ageing gulls often a good guess.
The only feature that immediately stands out as somewhat peculiar in Peters cachinnans being a 3cy - is the small mirror, as been said here. However, I would put more trust in the inner primary pattern - with their clean looking grey pattern with broad white tips. Tail pattern would be another clue. We are used to age cachinnans with a small mirror on p10 as 2cy, provided of course that other plumage features doesn´t stand out as to advanced for the given age. The variability stand out quite well when you look at varies 2 & 3cy, some 3cy have adult like secondaries, some not (while 2cy always have, and some with no visible mirror on the second gen. p10), large mirror on p10 and a smaller one on p9:

http://www.iesmeulmeester.nl/fotos.php? ... catsub=224

http://www.iesmeulmeester.nl/fotos.php? ... catsub=387

Note the brownish hue on the inner prmaries (significant or not):

http://waarneming.nl/foto/view/249854

Jan

Thanks for the interesting replies.
Apart from the small mirror on P10, the smooth brown pattern on hindneck and breast also struck me as unusual for 3c Caspian Gull.

apart from those smudgy marks on it's neck and the lack of mirrors on p9 and p10 it looks a lot like this 3cy photographed at Westkapelle on 13 November 2009.

regards, pim