Dark headed herring gulls

[Stefan]

Dark headed herring gulls

Dear all
On the 31st of March I saw a very dark headed herring gull on my “local” birding spot. Talking to my fellow birders, I obtained information of 3 other herring gulls with such dark heads, of which I send photos of two of these individuals.

Here is information about the 3 individuals
1) Photographs labelled “dark.herr.3.jpg”, “dark.herr.SE.jpg” and “dark.herr.SR.5.jpg” are taken at Bakkatjörn, Seltjarnarnes, SW Iceland, 31st of March 2012 by me. It may have slightly darker back compared to the other herring gulls so perhaps it is L. a. argentatus? As Antonio pointed out, L. michahellis atlantis should have white head at this time of year.
2) Photograph labelled as “dark.herr.OMAR” is taken on 25th of February 2010 from Þorlákshöfn, Reykjanes peninsula, SW Iceland by Ómar Runólfsson. There were some discussion on whether this individual could be L. smithsonianus, but this could not be verified as there are no photos of it in flight.
3) Photograph labelled as “dark.herr.YANN” is taken in Húsavík, NE Iceland in October, by Yann Kolbeinsson.

I would welcome your opinions on these gulls. I would think that such dark headed herring gulls are quite rare in Iceland, but I am not aware whether this is the case for other areas.

Best regards

Stefán