A small, dainty gull. Adults in summer have black heads, while young birds have a black mark on each wing which forms a 'W' pattern. In flight adults show a pale grey upperwing, with no black wingtips, and a very dark grey underwing.
https://www.rspb.org.uk/discoverandenjoynature/discoverandlearn/birdguide/name/l/littlegull/