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 "gwaeng-yi" gull, which means "cat" gull. In Hachinohe they are one of the 100 Soundscapes of Japan. The species is resident to coastlines of the East China Sea, Japan, Manchuria and the Kuril Islands. It is a vagrant to Alaska and North America and has been found in the Philippines. The bird is common in Japan, nesting from Hokkaido to Western Kyushu. It has caused flights to be delayed at Haneda Airport in Tokyo. An enormous gathering of black-tailed gulls can be found at the Kabushima at Hachinohe, Aomori, Japan. A Shinto shrine was raised by fishermen in 1269 (though