michahellis or argentatus? (1 Viewer)

lou salomon · May 19, 2006

hi,

this very big (male) 2nd winter --> 2nd summer gull has been resting for a short time near marburg, germany. the experts' opinions differ between herring and YLG. i'm curious about yours. i think it is herring, especially because of the large primary window seen in pic 4. ; sorry for blurry pics. taken by axel wellinghoff at 2. march 2006.

lou

Xenospiza · May 19, 2006

I think I agree with you: a Yellow-legged would usually have more fully grey coverts and its head shape appears to be wrong - the "bulge" on its forehead should be before the eyes in Yellow-legged.
(I consulted http://www.birdclubkatwijk.nl/bck/algemeen/inhome.asp?id=61 --- in Dutch, sorry).

JANJ · May 19, 2006

Hi both.

The gull is, due to blackish primaries with rounded tips, certainly a 3cy (2nd summer) type. As such one would expect a michahellis to be a little more advanced in regarding the plumage, and perhaps also a little darker concerning tone of grey parts, and more white-tipped tertials. It is the structure of the gull which make me see argentatus, both in the water and in the air, and the pale iner primaries, a very good pro-argentatus character, which of course both of you guys know.

JanJ

Th_SQ · May 19, 2006

A 3cy Larus argentatus for me also.

Isn't there the hint of a pale mirror on p10 on 2nd picture ? I think so. L. michahellis is said to never show this on a 3cy (from books).

Supporting characters are :
- little advanced moult
- pale grey newly moulted (but just compare the color of 1st and last picture !)
- dirty rump (as far as we can see from 2nd picture)
- pale underwing (obvious from 2nd picture but really not from 3rd and 4th ...)
- bill with extensive pale base
- window

I find for my part that head shape is more michahellis than argentatus (and that in fact it's not a very usefull character)

Just my opinion on this interesting bird :scribe:

michahellis or argentatus? (1 Viewer)

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lou salomon

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