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Photo by Marcus Martin, US Geological Survey.
Red-legged Kittiwake is one of the few species of gull that could rightly be called a "seagull." It nests on island cliffs at only four locations in the Bering Sea, and then essentially disappears at sea during the winter months. Populations of this kittiwake have dropped significantly at its main breeding site in the Pribilof Islands since the 1970s, probably due to low marine food productivity over an extended period of time. There is concern that commercial fishing might be one of the reasons that food supplies for kittiwakes and other animals has been reduced in the area. In addition, recent development of a harbor in the Pribilofs has increased fear of the accidental introduction of the Norway rat, a nest predator, to the islands.
Red-legged Kittiwake, because of its restricted range in the Bering Sea, is unlikely to be encountered except by fishermen and adventurous travelers. It is a small gull closely resembling the more widespread Black-legged Kittiwake except for its red legs and more curved yellow bill. In breeding plumage, adults have an all-white head, white underparts, a white tail, a gray back, and gray wings with black tips. During the non-breeding season, they have a black "smudge" on each side of the head, behind the eyes. Young birds also show these black facial marks, along with a grayish-black collar along the back of the head.
Red-legged Kittiwake's breeding distribution is limited to just four localities in the Bering Sea: Alaska's Pribilof Islands, Bogoslof Islands, and Buldir Island, and Russia's Commander Islands. More than 75% of the species' known population breeds on St. George Island in the Pribilofs. During the breeding season, Alaskan breeders can be found in the Bering Sea within 120-150 kilometers of their nesting sites. During the winter months, most of these birds are believed to leave the Bering Sea, but their exact whereabouts is not well-known; most sight records come from the northern Gulf of Alaska, or near the ice edge in the southeastern Bering Sea. Russian breeders winter in the northeastern Pacific Ocean.
At Red-legged Kittiwake's major nesting sites in the Pribilofs, the number of birds found on monitored plots has decreased by roughly 50% since the mid-1970s.
Like its more common relative the Black-legged Kittiwake, Red-legged Kittiwake nests on the ledges of vertical sea cliffs; the two species of kittiwake can often be found nesting in the same sites, together with murres. Red-legged Kittiwake nests are shallow cups made of mud, grass, and kelp. Both sexes construct the nest, and both perform incubation duties. Nests contain one egg, or sometimes two. Chicks are fed by both parents, and remain in the nest for over five weeks.
Red-legged Kittiwakes feed mainly on small fish (especially lampfish and Pollock), squid, and marine zooplankton. During the summer breeding period, this species is found foraging over deep water, ranging from 200 to 2,000 meters deep. These kittiwakes forage along the surface of the water, by either plunging or dipping into the water. Red-legged Kittiwakes often forage in flocks over schools of fish, sometimes in association with Black-legged Kittiwakes. Both species of kittiwake can feed during the day and night, but it has been suggested that Red-legged, with larger eyes, is better adapted for catching prey that migrate to the ocean surface during the nighttime. Very little is known about the migration of Red-legged Kittiwake away from its breeding sites, but if the species does spend the winter in the northern Pacific Ocean, as has been reported, it likely feeds in even deeper water than it does in the Bering Sea.
It is believed that excessive commercial fishing in the waters around the Pribilofs has diminished the food supply of Red-legged Kittiwakes and other marine animals that breed in the area, but this situation is not well-understood. Recent harbor construction and other development in the Pribilof Islands could potentially increase the chance of introducing Norway rats to the islands. Nest predation by rats would have a serious negative effect on Red-legged Kittiwake and other nesting seabirds on the islands.
In 1982, the U.S. Fish and Wildlife Service purchased kittiwake nesting cliffs in the Pribilof Islands, adding these sites to the Alaska Maritime National Wildlife Refuge, which already included nesting colonies at the other two Alaskan breeding sites. The species is also protected at its fourth breeding site in the Commander Islands, by virtue of its Endangered status in Russia.
In the Pribilof Islands, the species' breeding stronghold, there has been a proposal to ban trawl fishing in order to protect kittiwakes and other marine animals. In addition, a rat prevention program has been started to safeguard seabird nesting sites in the Pribilofs.
What Can You Do?
U.S. National Wildlife Refuges provide important habitat for Red-legged Kittiwake, and a great number of other species throughout the U.S. and its territories. Unfortunately, the refuge system is often under-funded during the U.S. government's budgeting process. To learn more about how you can help gain much needed funding for U.S. National Wildlife Refuges, visit: http://www.audubon.org/campaign/refuge_report/
Audubon's Important Bird Area program is another tool for the conservation of Red-legged Kittiwakes as well as other species. To learn more about the Important Bird Areas program in Alaska and to learn how you can help with the IBA program visit: http://www.audubon.org/bird/iba/ak.html
BirdLife International (2006) Species factsheet: Rissa brevirostris, Red-legged Kittiwake http://www.birdlife.org/datazone/species/index.html?action=SpcHTMDetails.asp&sid=3256&m=0
Byrd, G.V. and J.C. Williams. 1993. Red-legged Kittiwake (Rissa brevirostris). In The Birds of North America, No. 60 (A. Poole and F. Gill, Eds.) Philadelphia: The Academy of Natural Sciences; Washington, D.C.: The American Ornithologists' Union.
Kaufman, Kenn. 1996. Lives of North American Birds. Houghton Mifflin Company, New York.
Stattersfield, A.J., and D.R. Capper (Eds). 2000. Threatened Birds of the World. Lynx Editions and BirdLife International, Barcelona and Cambridge.