This picture was taken on 9th September 2017 at Grandcamp-Maisey, Normandy. Im not so good with Gulls as far as I can see there are one and a half GBB-Gulls, on the right a juvenile GBB-Gull, at the front Black Headed Gull. What is the bird on the left is it another GBB-Gull slightly older than the bird on the right.
Mike
Mike