Comments: these gulls are thought to be the most southerly
breeding Herring Gulls (argenteus) on the Atlantic coast. The
next taxon further south is the Cantabrican Atlantic Yellow-legged
Gull. The size, structure, bill markings, wing-tip pattern, moult
(typically P5 growing, P6 missing) and calls of these Herring Gulls
are similar to those of the Cantabrican form. The main difference
are:
1) leg colour which seems to be invariably pink in the Herring
Gulls.
2) mantle shade which is a paler grey in the Herring Gulls, as
they have a shade similar to that of normal argenteus.
Juveniles are generally like typical argenteus but they
usually show gleaming white rumps and completely black bills,
features normally associated with Mediterranean or Southern Atlantic
Yellow-legged Gull.