McKay’s Bunting Plectrophenax hyperboreus breeds on Hall and St Matthew islands (USA) (totalling c.300 km2) in the Bering Sea, and occasionally on St Lawrence and probably St Paul islands. It winters along the west coast of Alaska, from Kotzebue to the tip of the Alaska Peninsula, irregularly on the south coast of Alaska, occasionally to the Aleutian Islands and accidentally in British Columbia, Canada, and Washington and Oregon, USA. It is currently listed as Near Threatened under criterion D1+2 because it was thought to have a very small population (approximately 2,500 individuals, or 1,600-1,700 mature individuals), confined to a small breeding range on just four islands, but with no evidence of declines or significant threats.
However, recent population estimates suggest that the population size may be much greater than previously thought. Matsuoka and Johnson (2008) estimated the population size of McKay’s Buntings at 27,500-35,400 birds (5-11 times greater than previously reported), based on surveys conducted across its restricted breeding range on St Matthew and Hall islands.
If this estimate is confirmed, the species could warrant downlisting to Least Concern on the basis that it no longer approaches the thresholds for Vulnerable under any of the IUCN criteria. Although the total breeding range is small, the population, extent of occurrence, area of occupancy, area, extent or quality of habitat, and number of locations and subpopulations are not currently thought to be declining, suggesting that the species is unlikely to qualify as threatened or Near Threatened under criteria A, B, or C. However, breeding regularly at only two locations, if there was a plausible threat likely to cause rapid or very rapid future declines then the species could be listed as Near Threatened or even Vulnerable under criterion D2.
Further information is requested on the population size, trends and distribution of this species, and in particular whether there are plausible future threats which cold cause rapid or very rapid population declines within a short timeframe.
Matsuoka, S. M. and Johnson, J. A. (2008) Using a Multimodel Approach to Estimate the Population Size of Mckay’s Buntings. Condor 110(2): 371–376.