[order] Charadriiformes | [family] Laridae | [latin] Pagophila eburnea | [UK] Ivory Gull | [FR] Mouette blanche | [DE] Elfenbeinmöwe | [ES] Gaviota Marfilena | [IT] Gabiano ebureno | [NL] Ivoormeeuw

Ivoormeeuw determination

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The Ivory Gull is a medium-sized gull, approximately 10% larger and longerwinged than the Black-legged Kittiwake (Rissa tridactyla. It is distinctive at all ages, but is particularly striking in its pure white adult plumage. Immature birds have a dusky face, and black spots on the breast and flanks, tips of the primaries, and tail and outer wing coverts, although the extent of speckling is highly variable among individuals. The eye is dark, giving the bird a gentle expression. It exhibits a short period of immaturity for a gull of its size, acquiring adult plumage in its second winter. In adults, the bill is generally slate blue at the base, becoming pale yellow and tipped with red, but is darker in juveniles. The Ivory Gull has relatively short legs, which are black at all ages. Its round chest, short legs, and rolling gait give it a pigeon-like appearance when on the ground. However, although it is a stocky built bird, in the air it has a graceful and agile flight. Overall, the sexes are similar in appearance, and, once they reach maturity, there is little or no seasonal variation in characteristics.

In summer, Ivory Gulls are found in the High Arctic. The birds nest on granite, limestone, or gravel. Their main requirement for breeding is an opening in the ice where they can feed. In other seasons, Ivory Gulls are found along the edge of the pack ice.

Pagophila eburnea breeds in Greenland, Svalbard and arctic Russia, with Europe accounting for less than a quarter of its global breeding range. Its European breeding population is small (as few as 3,100 pairs), and underwent a large decline between 1970-1990. Although the species declined in Svalbard during 1990-2000, trend data were not available for its key populations in Greenland and Russia, and its overall trend was unknown. Nevertheless, its population size renders it susceptible to the risks affecting small populations, and consequently it is provisionally evaluated as Rare.
Ivory Gulls are arctic birds that range across Canada, Greenland, and arctic Western Europe. They are found throughout the Canadian Arctic and have also been seen on the pack ice off the Maritimes. Their breeding range is not well known as all nesting sites used prior to 1971 have been abandoned. Researchers believe this is because Ivory Gulls are not attached to specific breeding grounds. Ivory Gulls used to breed on northern Prince Patrick Island in the NWT, however current breeding grounds are not known. Ivory Gulls are assumed to breed on the High Arctic Islands.

Chiefly invertebrates and fish; also scavenges on faeces, carrion, and offal. Forages singly or in small groups, sometimes with Kittiwake, Grey Phalarope, and Sabine‘s Gull. Feeds by dipping-to-surface, surface-plunging, wading in shallow water, and surface-seizing. Scavenges on land and ice for faeces of seals, walrus, and polar bear, and at polar bear kills.

Pagophila eburnea has a near-circumpolar distribution in the Arctic seas and pack ice, breeding from north Canada through Greenland (to Denmark), Svalbard (Svalbard and Jan Meyan Islands (to Norway)) and islands off northern Russia. There are 4,500-22,000 individuals in the Russian Arctic, with 2,500-10,000 in European Russia, 4,000 on Severnaya Zemliya, and 8,000 on Franz Josef Land and Victoria Island; plus 500-700 in northeast Canada in 2002-200313, 500-1,000 in Greenland, and 50-200 in Svalbard, giving total of 15,550-23,900 individuals, perhaps best placed in the band 15,000-25,000 individuals. The population is possibly larger: aerial estimates of up to 35,000+ between Canada and Greenland were made in 1978-1979. The Spitsbergen population is probably decreasing, but on Victoria Island and Severnaya Zemlya no decrease has been detected. However, recent surveys have revealed that the Canadian populations have declined from 2,400 birds in 1987 to 500-700 birds in 2002-2003, representing an 80% decline in that period across the Canadian breeding range in all three known nesting habitat types. Birds have disappeared from 13 known and three suspected breeding colony sites. Declines may be linked to the decrease in Arctic sea ice cover (which declined 3% per decade from 1978 to 1998, and continues to shrink). For these reasons, the species has been precautionarily placed in the Near Threatened category, and further information is needed from the rest of the range, particularly from populations in the Russian Arctic. [conservation status from birdlife.org]

Ivory Gulls can live from 11 to 15 years. They become sexually mature when they turn pure white or during their second year. They often arrive at their breeding grounds before the snow melts, but they don't build a nest until the ground is sufficiently thawed. Exact timing is determined by the weather. Ivory Gulls nest on either flat ground or cliffs. Both sexes help build a nest of mosses, lichens, and grasses. The female lays one to three buff-coloured, spotted eggs. Both parents incubate the eggs, which hatch after 25 days. The chicks fledge after 11 days and begin feeding themselves after just 3 weeks.

The Ivory Gull has a circumpolar, but patchy, breeding distribution across the high arctic. Small, scattered colonies occur in Arctic Canada, Greenland, Spitzbergen, and the northern islands and archipelagoes of Russia in the Kara Sea. The wintering distribution of the Ivory Gull is poorly known but is generally along the southern edge of pack ice. In Canada, the Ivory Gull has a highly restricted range while breeding, nesting exclusively in Nunavut Territory. Present all year among pack-ice and drift-ice of Arctic Ocean, probably going ashore only to breed. Some evidence from Atlantic sector of southward movement for winter, as far as southern limits of drift-ice.