Slaty-backed Gull

The Slaty-backed Gull is a large gull from the North Pacific, recently accepted onto the official British list following verified records. It is similar in size to the Great Black-backed Gull but has a dark slate-grey back, pink legs and a distinctive string-of-pearls pattern on the wingtip formed by white spots on the primaries. It is among the rarest large gulls ever to reach Britain, and finding one requires careful scrutiny of large gull flocks at roost.