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
Fork-tailed storm petrel of the diet of river otters, gulls, and raptors. Further, introduced predators like foxes, martens, and raccoons have a significant impact on breeding populations. To defend themselves, fork-tailed storm petrels can eject their stomach oil at an incoming threat. Fork-tailed storm petrels generally coexist peacefully with other seabirds, where they can be seen sharing breeding habitat with tufted puffins. In some cases, aggression can be observed, where they are known to steal food from Leach's storm petrels. Being widespread and abundant, the fork-tailed storm petrel is not threatened with extinction. However, humans impact their life history in many ways. As