Nice educational shot Daniele. This is not ment in a degenerate way of course!

I rather believe that this is a Lesser Black backed gull instead of a Yellow Legged... Note tailpattern, head pattern, shouldermoult, inner primaries etc. But I don't know atlantis...I had'nt noticed that it was labelled as this subspecies.

>I rather believe that this is a Lesser Black backed gull instead of a >Yellow Legged... Note tailpattern, head pattern, shouldermoult, inner >primaries etc. But I don't know atlantis...I had'nt noticed that it was >labelled as this subspecies.

This is because this taxon (atlantis) is not well known by most people ... In fact, it is very similiar to Lesser black-backed Gull but there are lots of differences ..
Just for exapmle, the head/underparts is too dark for any Larus fuscus and the moult on the body is too advanced ... Rumo and uppertail coverts are to dark/spotted for fuscus. All the juv fuscus that I saw in the Azores were still in full juvenile plumage ...

Daniele

Location, dark tail and rump, dark outer greater coverts, dark head and breast, mean expression in the face and broad wing as a total package point to atlantis yellow-legged.

The characters together make it atlantis.

The moult is not too advanced for fuscus.
The rump and upperparts and tail easily fit graellsii, as does the dark head or the moult.
Fuscus can be as far or even further (with moulted wing-coverts too) at the start of October.

Theo Muusse

Thanks for the comments. Is there any chance atlantis is a candidate for a taxonomic split as seperate species?