Birdfinding.info ⇒ Due to the remoteness of its range, this Alaskan endemic is among the least-observed North American birds. Its usual breeding range comprises two uninhabited offshore islands, St. Matthew and Hall, that rarely appear on tour itineraries. It has been found fairly regularly at Gambell in spring, summer, and fall, and likely occurs year-round on St. Lawrence Island (which is very large and little-explored). It has also been recorded sporadically on St. Paul Island. The most accessible site where it can be found reliably is Nome, where it occurs from October to April. Since the early 2010s, small numbers have been found annually in winter on the Kenai Flats.
McKay’s Bunting
Plectrophenax hyperboreus
Endemic to Alaska: breeds on St. Matthew and Hall Islands in the northern Bering Sea. The global population has been estimated in the range of 27,500 to 35,400 (Matsuoka and Johnson 2008).
Small numbers also occur in summer on St. Lawrence Island and irregularly on St. Paul Island. There are nesting records from both islands.
Winters mainly along the western coast of Alaska from the Kotzebue area south to the Alaska Peninsula, and on Nunivak Island. Small numbers have recently been found wintering in south-coastal Alaska: most regularly on the Kenai Peninsula; more occasionally around Anchorage and on Kodiak Island—the distribution of records corresponds to winter observer coverage, so it presumably occurs more widely and regularly in unpopulated areas of south-coastal Alaska but goes undetected.
Casual in winter along the Pacific coast from southeastern Alaska south to Oregon. One summer vagrant has been recorded along the Beaufort Sea coast of the Yukon Territory (Herschel Island, July 2005). Has also been recorded from the Chukchi Peninsula, where it presumably occurs regularly.
Identification
McKay’s Bunting is likely to be confused only with its much more numerous and widespread relative, the Snow Bunting, which occurs throughout McKay’s’ small, remote Alaskan range. The adult male McKay’s is distinctive year-round, whereas female and first-winter McKay’s can be extremely similar to Snows. (See detailed comparison below.)
McKay’s Bunting, male in breeding plumage. (Gambell, St. Lawrence Island, Alaska; May 30, 2018.) © David Krueper
Males in breeding plumage are nearly all-white with contrasting black eyes and bill and black markings on the wings and tail.
McKay’s Bunting, male in nonbreeding plumage showing typical black markings on the wings and tail. (Icy View, Nome, Alaska; February 18, 2017.) © Julio Mulero
On the wings, the tips of the outer primaries are black and there are usually a few black spots on the scapulars and on the wrist. On the tail, the tips of the central tail feathers are usually black, but the tail can be all-white.
Nonbreeding males remain mostly white, with approximately the same pattern of black markings as on breeding males, but the bill turns yellow and they acquire an orangish or rusty wash on the crown and back, a rusty ear-patch, a rusty crescent on the side of the chest, and usually a few subtle dark streaks on the back.
McKay’s Bunting, male in nonbreeding plumage. (Icy View, Nome, Alaska; March 28, 2022.) © Richard Thunen
McKay’s Bunting, female in breeding plumage. (St. Matthew Island, Alaska; June 28, 2018.) © Bryce Robinson
Females in breeding plumage are white overall, with gray or blackish streaks on the back—but not on the rump. The female’s wings and tail are much more extensively black than the male’s, more similar to a male Snow Bunting, with mostly-black primaries, scapulars, and central tail feathers.
McKay’s Bunting in nonbreeding plumage with fairly extensive rusty markings. (Icy View, Nome, Alaska; December 8, 2016.) © Andrew Spencer
McKay’s Bunting, female in nonbreeding plumage showing faint streaks on the back. (Tsawwassen Ferry Terminal Jetty, Delta, British Columbia; December 10, 2019.) © John Gordon
Females in nonbreeding plumage and first-winter birds have faintly or moderately streaked upperparts, yellow bills, and rusty or orangish markings on the head, chest, and flanks. They can be indistinguishable from the palest nonbreeding Snow Buntings, but typically have an unmarked rump and all-white outer tail feathers.
Juveniles have pale-gray underparts and darker, streaked upperparts and wings.
McKay’s Bunting, juvenile. (St. Matthew Island, Alaska; June 30, 2018.) © Bryce Robinson
Voice. The vocalizations of McKay’s are not known to differ from the Snow Bunting’s. Breeding male gives a loud warbling song:Typical calls include: soft, musical rattles and twitters; a quick, fluty, descending whistle; and a brisk, nasal jrrt:
Notes
Monotypic species. Sometimes regarded as conspecific with the widespread Snow Bunting (nivalis), which it effectively replaces as a breeder on St. Matthew and Hall Islands in the northern Bering Sea.
After conducting a thorough analysis of plumage variation among McKay’s and Snow Bunting specimens collected in western Alaska, Withrow (2020) concluded that McKay’s is most appropriately classified as a subspecies of Snow. That conclusion was explicitly informed at least in part by the premise that McKay’s and Snow Buntings are allopatric. However, the tiny breeding range of McKay’s falls entirely within Snow’s enormous breeding range, and they have been known to occur together and hybridize at least occasionally both on St. Matthew and on islands where the Snow Bunting predominates, so it may be more accurate to regard them as effectively sympatric breeders. The persistence of McKay’s as a readily distinguishable form without substantial geographical isolation weighs in favor of full species status.
See below for comparison of McKay’s Bunting with the Snow Bunting.
Cf. Snow Bunting. McKay’s Bunting may be regarded as either a separate species or a distinctive, highly localized form of Snow Bunting. They occur together year-round throughout McKay’s’ very limited range, which comprises a just few islands and coasts of the Bering Sea. McKay’s has been found several times in winter outside of its normal range, from south-coastal Alaska south to Oregon and once in summer along the northern coast of the Yukon Territory.
McKay’s Bunting, male in transition into breeding plumage. (Icy View, Nome, Alaska; March 27, 2022.) © Scott Page
Snow Bunting, male in typical breeding plumage, with a solid-black back. (Utqiaġvik, Alaska; June 28, 2022.) © Timothy Piranian
As a general rule, McKay’s Buntings in all plumages have more white feathering and less black feathering than Snow Buntings in the equivalent plumage, but the differences are not always clear-cut. Some individuals in some plumages may not be identifiable—and hybrids have been known to occur. Nevertheless, male McKay’s are readily identifiable year-round based on the coloration of their backs and the patterns on their wings and tails.
Snow Bunting, an exceptionally pale male in transition into breeding plumage—if it had been photographed in or near Alaska, this individual would likely be identified as a female McKay’s Bunting. (Whitby, Ontario; March 2, 2014.) © Ed McAskill
McKay’s Bunting (as identified by the photographer) in nonbreeding, possibly first-winter plumage—not readily distinguishable from a Snow Bunting based on this photo. (Icy View, Nome, Alaska; March 27, 2022.) © Richard Thunen
Back Coloration: In breeding plumage, male McKay’s has all-white body feathers above and below, whereas male Snow has an extensively black back. In winter, male Snow Buntings’ backs change from black to a streaky blend of black and rusty-brown. Nonbreeding male McKay’s often show some subtle streaking on the back, but remain much whiter above than any Snow Bunting.
Snow Bunting in nonbreeding plumage, showing black central tail feathers and thin black lines on the outer webs of the outer tail feathers. (Baie-du-Febvre, Nicolet-Yamaska, Quebec; January 21, 2022.) © Daniel Jauvin
McKay’s Bunting, male in nonbreeding plumage showing black on the tips of the outer webs of all the tail feathers. (Icy View, Nome, Alaska; March 28, 2022.) © Scott Page
Wing Pattern: Male McKay’s has a small and variable amount of black on the wings, usually confined to the tips of the primaries, and often a few black streaks or spots on the scapulars and alula (wrist). Male Snow Buntings usually have entirely black primaries and alula, and all-black scapulars in breeding plumage. In their nonbreeding plumage, the scapulars match the back coloration. However, they vary widely in the extent of black in their wings, with the palest male Snows showing essentially the same pattern as the darkest male McKay’s.
Snow Bunting in nonbreeding plumage, showing black primaries and central tail feathers. (Ottawa, Ontario; January 27, 2021.) © Ken & Fay Broten
McKay’s Bunting, male showing black wingtips and almost entirely white tail feathers. (Icy View, Nome, Alaska; February 18, 2017.) © Julio Mulero
Tail Pattern: There is generally little overlap in their tail patterns. On male Snow Buntings the six central tail feathers (i.e., three on each side) are entirely black, and the outer tail feathers typically have black outer webs near the tip. Male McKay’s typically show very little black on their tails, usually limited to the tips of the two or four central tail feathers. Some male McKay’s have more extensive black on these feathers.
McKay’s Bunting, male showing limited black spots on the tail. (Icy View, Nome, Alaska; March 23, 2023.) © Josiah Verbrugge
McKay’s Bunting, male in breeding plumage with atypically extensive black on the tail. (Gambell, St. Lawrence Island, Alaska; May 31, 2018.) © Joe Wing
Female McKay’s and Snow are somewhat more similar than the males, and may not be distinguishable in all cases. The key differences are: (1) the extent of white in the rump area; (2) the breadth of the white streaks on the back; (3) the presence or absence of dark streaks on the outer webs of the three outer tail feathers; and (4) the extent of white on the inner primaries and outer secondaries. In all of these features, female McKay’s typically has more white and less black than female Snow. However, judging from the comparisons of specimens presented by Withrow (2020), there appears to be at least marginal overlap in each of these features, such that the darkest female McKay’s and palest female Snow would be effectively identical.
McKay’s Bunting, female in breeding plumage, showing streaked back, white rump, and all-back central tail feathers. (St. Matthew Island, Alaska; June 28, 2018.) © Bryce Robinson
Snow Bunting, female in typical breeding plumage. (St. Paul Island, Alaska; May 25, 2015.) © Nigel Voaden
In their nonbreeding and transitional plumages, female McKay’s and both sexes of Snow Bunting can be much more difficult to distinguish. All have variably streaked backs orangish or rusty-brown markings on the head.
McKay’s Bunting in nonbreeding plumage—apparently a relatively dark male based on the absence of visible black in the tail. (Icy View, Nome, Alaska; December 8, 2016.) © Andrew Spencer
Snow Bunting in typical nonbreeding plumage. (Caldeira Seca, Morro Alto Natural Forest Reserve, Flores, Azores, Portugal; October 22, 2023.) © Jean-Louis Carlo
Many nonbreeding Snow Buntings have heavily streaked upperparts, including the rump, and extensive markings on the head and chest, sometimes extending down to the flanks. But many have all-white rumps, faintly streaked backs, and mostly white heads and chests. The palest nonbreeding Snow Buntings may be indistinguishable from female McKay’s.
McKay’s Bunting, female in nonbreeding plumage. (Tsawwassen Ferry Terminal Jetty, Delta, British Columbia; December 8, 2019.) © Liron Gertsman
Snow Bunting in transition into nonbreeding plumage. (Crooked River Wetlands Complex, Oregon; November 13, 2023.) © Tom Crabtree
More Images of McKay’s Bunting
McKay’s Bunting, female in nonbreeding plumage. (Damon Point, Ocean Shores, Washington; February 12, 2012.) © Knut Hansen
McKay’s Bunting, males. (Icy View, Nome, Alaska; March 27, 2023.) © Aaron Lang
References
Alderfer, J., and J.L. Dunn. 2021. National Geographic Complete Birds of North America (Third Edition). National Geographic Society, Washington, D.C.
BirdLife International. 2020. Plectrophenax hyperboreus. The IUCN Red List of Threatened Species 2020: e.T22721046A137357547. https://dx.doi.org/10.2305/IUCN.UK.2020-3.RLTS.T22721046A137357547.en. (Accessed July 9, 2024.)
Brazil, M. 2009. Birds of East Asia. Princeton University Press.
eBird. 2024. eBird: An online database of bird distribution and abundance. Cornell Lab of Ornithology, Ithaca, N.Y. http://www.ebird.org. (Accessed July 9, 2024.)
Matsuoka, S. M., and Johnson, J. A. 2008. Using a multimodel approach to estimate the population size of McKay’s Buntings. Condor 110:371-376.
Sibley, D.A. 2014. The Sibley Guide to Birds (Second Edition). Alfred A. Knopf. New York.
Withrow, J. 2020, Plumage Variation in Bering Sea Plectrophenax Buntings and the Specific Status of McKay’s Bunting. Western Birds 51:174-189.
Xeno-Canto. 2024. McKay’s Bunting – Plectrophenax hyperboreus. https://xeno-canto.org/species/Plectrophenax-hyperboreus. (Accessed July 9, 2024.)