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 shown in any animal other than humans. Two to four eggs are laid in a cup nest in a fork high in a tree. Drongos are brood hosts for African Cuckoos and Jacobin Cuckoos. Its populations are genetically highly structured, and four races are accepted. The races "D. a. modestus" (Príncipe) together with "D. a. coracinus" and "D. a. atactus" (Bioko to west and central mainland Africa, from Guinea east to western Kenya and south to Angola) are usually split as a separate species, the velvet-mantled drongo, "D. modestus" (Hartlaub, 1849). Fork-tailed drongo The fork-tailed drongo, also called the common