Hi John and all,
From looking at the photo's it looks OK for a YL Gull. I have for several years, been of the opinion that we get 2 types of YL Gull in our region. The early to late autumn (Aug-Oct) we get, are what I consider to be Atlantic YL Gulls (not atlantis) but gulls that have bred along the Spanish/Portugese atlantic coast. These birds show streaking around the eyes and light streaking on the head and appear a slightly lighter shade of grey to the classic bright white headed/ darker grey mantled birds that I see in the Belvide roosts from November onwards, which I consider to be proper Mediterranean birds. These birds also tend to be in active wing moult at this time of year, so it is harder to see the pattern on the underside of p10, which can be still growing. I guess these streaky headed birds are part of the intergration between the Med michahellis population and the proper streaky (atlantis) azorian birds.
Them's me onions:t: