Sabine's gull treated as comprising a monotypic genus; it is only placed within the genus "Larus" when the genus is enlarged. The black bill and notched tail are almost unique within the gulls, as they are shared only with the swallow-tailed gull of the Galapagos. On the basis of this the two species were often thought to be each other's closest relatives, a hypothesis ruled out by a number of behaviour and ecological differences. Mitochondrial DNA studies confirmed that they are not closely related, and the closest relative of the Sabine's gull is now thought to be the ivory gull, another Arctic
Black-tailed gull it has been rebuilt several times since) at which the black-tailed gull, is seen as a messenger of the goddess of the fishery. For over 700 years, the species has enjoyed reverence, feeding and protection from the local population. As a result, every summer, over 40,000 black-tailed gulls nest and raise their young in the grounds of the shrine and the surrounding island, which has been designated a National Natural Monument by the government of Japan. The gulls are very tame and are a popular local tourist attraction. Around 5,000 birds also nest at Fumi-shima in Shimane Prefecture near Izumo