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
Four-letter word words of this length are upsetting to some, for religious or personal sensitivity reasons, such as: "" (UK), "", "", "", and "" (UK). Racist, ableist, and slurs pertaining to an individual's sexual orientation may also qualify, such as "" (in the UK not a racial slur, but short for Mongol, or someone with Down syndrome - previously called Mongolism), "", "", "", "", "" and "". Several "four-letter words" have multiple meanings (some even serving as given names), and usually only offend when used in their vulgar senses, for example: "", "", "" (UK) and "" (UK). A borderline