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Not a Caspian Gull surely | Choshi, Japan march 2020 (1 Viewer)


Well-known member
Choshi harbour, Chiba, Japan | 5 march 2020

records at:

I fail to draw a crowd to my gull topics but hey...if i can't try it here....
This was one of many gulls that drew my attention. Most were at a distance, but this one was nearby -next to a probable Thayer's-.
Ok the light is bleaching out the image a bit but the head is whitish, neck finely streaked, so is the breast...
I don't see a dark trailing edge to the secondaries (if you call them that) like in Vega Gull
I would label this gull 3CY but it could also be an advanced 2CY?

What do you think? Vega Gull would be the standard light mantled gull I suppose but I don't think that is what this is, for one the eye is dark, not yellowish/green.
It has a cachinnans look about it. I have heard talk of light-mantled Heuglin's or maybe taimyrensis but I am only just starting to see what Vega is, so...

anti Caspian Gull:
the bill is a bit heavy,
the dark tailband is too broad

what would you say?

hope to read from you


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Well-known member
I'll leave this one to somebody who knows what they are talking about, but I don't get a Caspian vibe from this bird. The gonydal angle and aggressive expression seem at odds for that species.

lou salomon

the birdonist
I have no personal experience with all these eastern pacific taxa but i think a 2nd winter-->summer, or in other words, 3cy Mongolian Gull would be the best fit for this bird. it would be way too advanced for a 2nd cycle (3cy) Vega Gull and lack of clear white primary tips also suggests a 2nd cycle bird.


Well-known member
thanks DMW and Lou,
I am going to look into it, it would be a nice one to have. Mongolian appear to be common there but I had no acceptable shots yet (only some distant birds which may well be advanced Vega anyway)

Up to now I can't find an example of another argenteus-like light mantled Mongolian.

cheers and thanks again for the quick reply! Much appreciated


Well-known member
A gullist has spoken, this too is a Vega Gull, a 3CY. ( a Choshi-experienced admin has ID-d the bird at observado.org)

case closed I think



Well-known member
Hi Lou, yes it was Peter A.
Loosely translated:

The bird has a typical dirty brown neck and mainly white secondaries of a 2ndW Vega. Plumage is also still very fresh

"De vogel heeft de typisch vuilbruine halstekening, witte vleugeldekveren en grotendeels witte armpennen van een 2w Vegameeuw. Erg vers verenkleed ook nog altijd." (https://japan.observation.org/waarneming/view/210272487)

I admit now that i can't follow his line of thinking completely...as a gullist beginner.

In the rest of his comment he seemed to say that Mongolian is probably less frequent in Eastern JP.

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