156917 Great Black-backed Gull - Larus marinus. L 64-79cm. Our largest gull species. Bulkier than Lesser Black-backed, adult with darker back, massive bill and pink legs. Sexes are similar. Adult has almost uniformly dark back and upperwings; wingtips only marginally darker than rest of wings. Note white patch at tip of wings and broad white trailing edge. Plumage is otherwise white. Bill is yellow with an orange spot. Juvenile and 1st winter are mottled and streaked grey brown. In flight, brown upperwings have pale panels and inner primaries. Bill is dark, legs are dull pink and whitish tail is dark-tipped. Adult plumage acquired over 3 years. Voice Utters a deep kaa-ga-ga call. Status Local and coastal in the breeding season. Often nests in vicinity of mixed seabird colonies and pairs are territorial. Outside breeding season, more widespread inland and numbers boosted by migrants from N Europe.