Ivory gull narrower os pubis, and potentially more flexibility in skull kinetic structure. Structurally, it is most similar to the kittiwakes; however, recent genetic analysis based on mtDNA sequences shows that Sabine's gull is the ivory gull's closest relative, followed by the kittiwakes, with Ross's gull and swallow-tailed gull sharing a clade with these species. "Pagophila" is maintained as a unique genus because of the bird’s morphological, behavioral and ecological differences from these species. Colloquial names from Newfoundland include slob gull (from "slob", a local name for drift ice) and ice partridge, from a vague resemblance to a ptarmigan. This species is
Glaucous gull 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 or other large seabird. The specific "hyperboreus" is Latin for "northern" from the Ancient Greek "Huperboreoi" people from the far north "Glaucous" is from Latin "glaucus" and denotes a bluish-green or grey colour. This gull is migratory, wintering from in the North Atlantic and North Pacific oceans as far south