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.
Ivory gulls are small birds that spend most of their life in the high Arctic. These birds are easily recognized by their pure white plumage. They have a thick blue bill with a yellow tip, and black legs. The bill is tipped with red, and their eyes have a fleshy, bright red eye-ring in the breeding season. Young birds have a dusky face and variable amounts of black flecking in the wings and tail; they take two years to attain full adult plumage.
Ivory gulls breed in the high Arctic and have a circumpolar distribution through Greenland, northernmost North America, and Eurasia. In North America, they only breed in the Canadian Arctic. During the winter, Ivory gulls live near polynyas - a large area of open water surrounded by sea ice. Wintering gulls are often seen on the eastern coasts of Newfoundland and Labrador and occasionally appear on the north shore of the Gulf of St. Lawrence and the interior of Labrador. They also winter from October through June in the Bering Sea and Chukchi Seas. Ivory gulls breed on rocky islands and cliffs near pack ice, rocky mountains, plain polar desertsб gravel, and sandy spits, or on bare rocky ground.
Ivory gulls are gregarious birds especially during the breeding period when they nest in big colonies. These birds are active during the day; they feed mainly on the surface by hovering above the water. Ivory gulls migrate only short distances south in autumn with most of the population wintering in northern latitudes at the edge of the pack ice. However, some birds may reach more temperate areas. Ivory gulls communicate vocally and their flight call cry is a harsh, tern-like 'keeeer'. They have also many other vocalizations, including a warbling "fox-call" that indicates potential predators such as an Arctic fox, Polar bear, Glaucous gull, or human near a nest. A "long-call" is given with wrists out, elongated neck, and downward-pointed bill; it is used in the elaborate display to other Ivories during breeding. A plaintive begging call is usually given in courtship by females to males, accompanied by head-tossing.
Ivory gulls are carnivores (piscivores) and scavengers. They eat fish and crustaceans, rodents, eggs, and small chicks. They are also opportunist scavengers and are often found on seal or porpoise corpses. They often follow polar bears and other predators to feed on the remains of their kills.
Ivory gulls are monogamous; they form pairs in which both males and females stay with only one partner. Their breeding season varies with location and pairs nest in colonies. The female lays 1 to 3 olive eggs in a ground nest lined with moss, lichens, or seaweed. The incubation lasts around 25 days done by both parents. At hatching, the chicks are precocial. They are mobile and covered with white down. Both parents feed and brood them during the first days. The young usually stay in the nest until they fledge for about 5-7 weeks and become reproductively mature in their second year of life.
The major threats to Ivory gulls include illegal hunting and habitat loss due to the decline in sea ice. As Ivory gulls breed near sea ice the loss of this habitat may make it difficult to feed their chicks. Other threats include climate change, pollution, oil spills, and disturbance at colonies. Ivory gulls also suffer from heavy predation during the nesting period by local predators which can destroy entire colonies and take eggs and nestlings.
According to the IUCN Red List, the total Ivory gull population size is around 58,000-78,000 individuals, roughly equivalent to 38,000-52,000 mature individuals. Specific populations of the species have been estimated in such areas: 1,000-1,500 breeding pairs on Franz-Josef Land (European Russia); 1,500-3,000 pairs on Severnaya Zemlya; 1,000-2,500 pairs in the rest of the Kara Sea Islands (Central Asian Russia); 1,000 pairs - in northeast Canada; 900-2,000 pairs in Greenland and 800-1,500 pairs in Svalbard. Overall, currently, Ivory gulls are classified as Near Threatened (NT) on the IUCN Red List and their numbers today are decreasing.