Darryl and I arrived on the Azores today for Autumn 2016. We are on Sao Miguel for the next two days. Only had a couple of hours today. Highlights were a fly-by Wilson's Phalarope on seawatch and a Michahellis-type Yellow-legged Gull amongst the Azores Yellow-legged Gulls.
Mich-type YLG. The juvenile mantle and scaps point towards a late fledgling, or could indicate moult retarded due to vagrancy pressures. The pale inner primary window points towards YLG complex rather than LBB. Possibly a YLG ssp from one of the other Atlantic Islands? Certainly a lot of features outside the known range of variation of Azores YLG.