The ivory gull (Pagophila eburnea) is a small gull, the only species in the genus Pagophila. It is a resident breeding bird in the high Arctic and has a circumpolar distribution through Greenland, northernmost North America, and Eurasia.
Taxonomy
The ivory gull was initially described by Constantine Phipps, 2nd Baron Mulgrave in 1774 as Larus eburneus from a specimen collected on Spitsbergen during his 1773 expedition towards the North Pole. Johann Jakob Kaup later noted the unique traits of the ivory gull and gave it a monotypic genus Pagophila in 1829. Today only a few authors consider the ivory gull not deserving of its monotypic genus, instead choosing to merge it, along with the other monotypic gulls, back into Larus.
This gull has traditionally been believed to be most closely related to either the kittiwakes, Sabine's gull, or Ross's gull. Pagophila is maintained as a unique genus because of the bird's morphological, behavioural and ecological differences from these species.
Description
The ivory gull is long, with a wingspan of ; males weigh between and females between .
This species is easy to identify. It has a different, more pigeon-like shape compared to the Larus gulls, an impression reinforced by its short legs.
Diet
It takes fish and crustaceans, eggs and small chicks but is also an opportunist scavenger, often found on seal or porpoise corpses. It frequently follows polar bears and other predators to feed on the remains of their kills, and also eats polar bear and seal faeces, and seal placentae. and 8,000 on Franz Josef Land and Victoria Island. There were also estimated to be around 4,000 individuals in Greenland and in the years 2002–03, 500–700 were recorded in Canada. The species is declining rapidly in Canada, while in other parts of its range its population is poorly known. The Canadian population in the early 2000s were approximately 80% lower than in the 1980s. There is a high risk that the ivory gull could become the first vertebrate to become extinct due to human-induced global warming.
The species is classified by the International Union for Conservation of Nature as "Near Threatened".