The Ivory Gull (Pagophila eburnea) is a small gull, the only species in the genus Pagophila. It breeds in the high Arctic and has a circumpolar distribution through Greenland, northernmost North America, and Eurasia.
The ivory gull was initially described by Constantine Phipps, 2nd Baron Mulgrave in 1774 as Larus eburneus from a specimen collected on Spitsbergen. Johann Jakob Kaup later recognized the unique traits of the ivory gull and gave it a monotypic genus, Pagophila, in 1829. Johan Ernst Gunnerus later gave the species a new specific name, Pagophila alba. The scientific names Eburnea and Pagophila mean "Ivory-Coloured" and "lover of sea ice" from the Latin ebur for ivory and the Greek pagos for sea-ice respectively.
This gull has traditionally been believed to be most closely related to either the kittiwakes, Sabine's gull, or Ross's gull. It differs anatomically from the other genera by having a relatively short tarsometatarsus, a 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.
This species is easy to identify. At 17 in, it has a different, more pigeon-like shape than the Larus gulls, but the adult has completely white plumage, lacking the grey back of other gulls. The thick bill is blue with a yellow tip, and the legs are black. Its cry is a harsh eeeer. Young birds have a dusky face and variable amounts of black flecking in the wings and tail. The juveniles take two years to attain full adult plumage.
In North America, it only breeds in the Canadian Arctic. Seymour Island, Nunavut is home to the largest known breeding colony, while Ellesmere, Devon, Cornwallis, and north Baffin islands are known locations of breeding colonies.
During the winter, ivory gulls live near polynyas, or a large area of open water surrounded by sea ice. North American birds, along with some from Greenland and Europe, winter along the 2000 km of ice edge stretching between 50° and 64° N from the Labrador Sea to Davis Strait that is bordered by Labrador and southwestern Greenland. Records of individuals as far south as California and Georgia have been reported.
Ivory gulls migrate only short distances south in autumn, most of the population wintering in northern latitudes at the edge of the pack ice, although some birds reach more temperate areas.
These photos were taken at Svalbard. They commonly associate with polar bears.
It takes fish and crustaceans, rodents, eggs and small chicks but is also an opportunist scavenger, often found on seal or porpoise corpses. It has been known to follow polar bears and other predators to feed on the remains of their kills. The captain of our ship found the polar bear show here buy first seeing the Ivory Gulls.
In 2012 the total population of ivory gulls was estimated to be between 19,000 and 27,000 individuals. The majority of these were in Russia with 2,500-10,000 along the Arctic coastline, 4,000 on the Severnaya Zemlya archipelago and 8,000 on Franz Josef Land and Victoria Island. There were also estimated to be around 4,000 individuals in Greenland and in 2002-2003 500-700 were recorded in Canada.
The species is rapidly declining in Canada, while in other parts of its range its population is poorly known. Illegal hunting may be one of the causes of the decline in the Canadian population.