On February 22, 2019, I found a possible Azorean Yellow-legged Gull in Peniche (west mainland Portugal). This subspecies is characterized by a well defined hood. Judging by the color of the bill and a slight brownish hue on the coverts, I would say the bird is in its third winter (4th calendar year).
The bird did not allow good photos, particularly in flight, however, here are some photos with some notes

This record will be submitted to the Portuguese Rarities Committee.