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
Iceland gull Iceland gull The Iceland gull ("Larus glaucoides") is a medium size gull which breeds in the Arctic regions of Canada and Greenland; although not in Iceland (as its name suggests), where it is only seen during winter. The genus name is from Latin "Larus" which appears to have referred to a gull or other large seabird. The specific "glaucoides" denotes its resemblance to "Larus glaucus", a synonym of "Larus hyperboreus", the glaucous gull; "-oides" is Ancient Greek and means "resembling". It is migratory, wintering from in the North Atlantic as far south as the British Isles and northernmost states of