lusitanius Yellow-legged Gull
lusitanius 2cy Jan
lusitanius 3cy Jan
lusitanius 4cy Jan
lusitanius ad Jan
Yellow-legged Gull lusitanius 1cy, November 07 2012, Peniche, Portugal. Picture: Rui Caratão.
Some birds have coverts replaced in post-juvenile moult, others have a complete juveile covert panel. Also, quite some birds have not completed yet the moult in the scapular region.
Large birds with advanced post-juvenile moult, white head and much white in tail probably michahellis michahellis, like bird in second image.
Warning: by November, the Atlantic coast of Portugal holds large numbers oif birds, including Lesser Black-backed Gulls (graellsii / intermedius), Mediterranean Yellow-legged Gulls (michahellis michahellis) and of course local birds (michahellis lusitanius). Sometimes, these three taxa may appear extremely similar, and ID is tentative. However, extremes of all forms are rather straightforward, especially for bird watchers from the region.
below: 1cy michahellis michahellis.