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
Fork-tailed storm petrel is along the coast of the northern Pacific Ocean, extending from northern California to northeast Asia. They mainly feed on planktonic crustaceans, small fish and squid, but will also consume offal. Similarly to other storm-petrels, it forages by picking food of the surface of the water while in flight. The fork-tailed storm petrel is small seabird that is 20 cm in length with a wingspan of 45.9 cm. Its foraging behaviour resembles other storm-petrels, where it flies with short stiff wingbeats close to the surface of the water. Despite its name, the forked tail in this bird is not always