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
Glaucous gull a lined nest on the ground or cliff. Normally 2–4 light brown eggs with dark chocolate splotches are laid. These are omnivores like most "Larus" gulls, and they will eat fish, insects, molluscs, starfish, offal, scraps, eggs, small birds, small mammals and carrion as well as seeds, berries and grains. Glaucous gull The glaucous gull ("Larus hyperboreus") is a large gull, the second largest gull in the world, which breeds in Arctic regions of the Northern Hemisphere and winters south to shores of the Holarctic. The genus name is from Latin "Larus", which appears to have referred to a gull