McKay's Bunting

Plectrophenax hyperboreus

U.S. Fish & Wildlife Service
  • EMBERIZINAE
  • Sparrows, Buntings, Towhees, Longspurs
  • 6,000

One of North America's rarest songbirds, McKay's Bunting breeds only on two small islands in the Bering Sea. It has never been closely studied, but is is thought to share many behavioral and ecological characteristics with the Snow Bunting, from which it is believed to have evolved. At the moment it faces no immediate threats to survival, but given its small population, tiny range, and ground-nesting habits, it may be extremely vulnerable to introduced mammalian predators.

Identification
This species closely resembles Snow Bunting in all plumages, but is whiter overall. The breeding plumage of the male is almost purely white, with only small areas of black on the wingtips and tail. The breeding female has a streaked back. Non-breeding birds also have warm brown patches on cheeks, crown, and the the sides of the neck.

Distribution and Population Trends
Breeds on Hall and St. Matthew islands in the Bering Sea. May occasionally breed on St. Lawrence Island and St. Paul Island, also in the Bering Sea. Stays on breeding grounds from May to early October. Winters on the western coast of Alaska, from Kotzebue south to the Alaska Peninsula.

Formal census data for this species have not been collected. Taking known density figures for Snow Bunting and applying them to the area of the islands where McKay's Bunting breeds, one can roughly calculate an overall population size between 2,800 and 6,000 birds. It is highly likely, however, that the population is much smaller, because much land on the islands is not suitable for breeding.

Ecology
Nests on shingle beaches in hollow drift logs and rock crevices. Winters on coastal marshes, shingle beaches, and agricultural fields. Feeding habits are thought to be similar to Snow Bunting, which in winter consumes seeds from weeds and grasses, and in summer has a mixed diet of seeds, buds, and insects.

Threats
There appear to be no immediate threats to the species, but its tiny breeding range, small population size, and probable lack of evolved defenses against predators leave it highly vulnerable to introduced species such as rats, foxes, or weasels.

Conservation
Further study of the behavior, ecology, and demographics of this bird are needed. The continued survival of the species likely depends heavily on protection of its breeding grounds.

What Can You Do?
Audubon's Important Bird Area program is a vital tool for the conservation of McKay's Bunting as well as other species. To learn more about the Important Bird Areas program in Alaska and how you can help, visit: http://www.audubon.org/bird/iba/.

References
Lyon, B., and R. Montgomerie. 1995. Snow Bunting and McKay's Bunting (Plectrophenax nivalis and Plectrophenax hyperboreus). In The Birds of North America, No. 198-199 (A. Poole and F. Gill, eds.). Philadelphia: The Academy of Natural Sciences; Washington, DC: The American Ornithologists' Union.