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 drongo-cuckoo known how or whether the drongo-like appearance benefits this species but it is suspected that it aids in brood-parasitism just as hawk-cuckoos appear like hawks. Some recent work suggested that the species was conspecific with the square-tailed drongo-cuckoo and together known as the Asian drongo-cuckoo, but should be split based on call and morphological differences. Fork-tailed drongo-cuckoo The fork-tailed drongo-cuckoo ("Surniculus dicruroides") is a species of cuckoo that resembles a black drongo. It is found resident mainly in peninsular India in hill forests although some specimens are known from the Himalayan foothills. It can be easily distinguished by its straight