I had 10 days working in Spain (18-28 May) so took the chance to visit the Ebro Delta and have a look at some michahellis. I was especially interested in the 2cy birds - a selection of which is shown here. All were photographed at Sant Carles de la Rapita, on the Southern shore of the delta.
The image above and the three below are all of the same individual. Variability in 2 cy birds at this time of year is bewildering, but all very different to how our British Herring Gulls are looking right now.