www.gull-research.org

Pictures by Yves BLAT on 6.1.16 at the landfill site of Gueltas, Morbihan, Brittany, France.

Yves asks:
L. g. glaucoides or kumlieni?

This bird mostly recalls glaucoides to my eyes. The only odd thing about it could be the solid tail-band, which is found commonly in kumlieni. For kumlieni, the outerwebs of the outer primaries should be darker.