North American Birds

VOLUME 70 NO3-NO4 2019

A Quarterly Journal of Ornithological Record Published by the American Birding Association. The mission of the journal is to provide a complete overview of the changing panorama of our continent’s birdlife.

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260 N O R T H A M E R I C A N B I R D S RED-BACKED SHRIKE IN ALASKA a definite identification cannot be achieved." Brown Shrike breeds as close to Alaska as the western Anadyr River basin in north- east Russia, then west and south to north- eastern China, northern Korea, and north- ern Mongolia. It winters from Southeast Asia, the Philippines, and Borneo west to India. There are four recognized subspecies. Nominate cristatus is the most northerly, from the Anadyr south to Kamchatka and Mongolia, and it winters in Southeast Asia. Subspecies L. c. lucionensis breeds in east- ern China and very locally Korea, perhaps still in southern Japan, and it winters from southern Southeast Asia to the Philippines, Borneo, and the Moluccas. L. c. confusus, which some authorities (e.g., Worfolk 2000, Moores 2015) believe might be an intergrade between nominate cristatus and lucionensis (and in some areas, with superciliosus), nests in southeast Russia, northeast China, and northeast Korea, and it winters in southern Southeast Asia to the Philippines and Borneo. Subspecies L. c. superciliosus nests in coastal Russian Far East (e.g., Sakhalin, Kuriles) and northern Japan and winters primarily in the Greater and Lesser Sundas. Overall, Brown Shrike is a very rare to casual visitor in both spring and (mostly) fall to western Alaska islands and is a casual vagrant from main- land Alaska south to California in fall and winter. There is also one late-fall record from Nova Scotia. Records from North America most likely involve nominate cristatus, and the only individuals to be identified with certainty to subspecies there are two speci- mens from Alaska, which are indeed cristatus (Gibson and Withrow 2015). Brown Shrike is a casual vagrant westward as far as the U. K. (Slack 2009, www.tarsiger.com, www. netfugl.com, https://waarneming.nl), where there are almost 25 records. Turkestan Shrike, split from Isabelline Shrike by some authorities (e.g., Gill and Donsker 2017), breeds from Iran and south - west Pakistan to southern Kazakhstan, ex- treme northwest China, and the southern Altai region of Russia at about 85 °E. It is believed to winter largely in eastern Africa, although both its and Isabelline's non-breed- ing ranges are incompletely known (Worfolk 2000). (See Isabelline Shrike, below, for va- grancy in Turkestan Shrike.) Isabelline Shrike nests from the Altai region and Mongolia to north-central China, and it winters from the Arabian Peninsula and east - ern Africa east to western India. Nominate isabellinus ("Daurian Shrike") nests from cen - tral Russia to Mongolia and northern China, long-distance migrants. Information on the core ranges, below, are largely from Worfolk (2000), Slack (2009), Dickinson and Christidis (2014), and Pyle et al. (2015). These shrikes have had a somewhat complex taxonomic history, treated variously since the 1950s as just one, two, three, or the cur- rent four species (Worfolk 2000, Slack 2009, Panov et al. 2011, Pyle et al. 2015). Red-backed Shrike breeds from western Europe east to the Altai region of central Russia, northern Kazakhstan, and northwest China (Xinjiang), between 85 and 90 °E. It winters primarily in southern Africa. As a va- grant, Red-backed has occurred northward to Iceland and eastward to Japan (at least six records; OSJ 2012, Y. Odaya in litt.), Korea (four or five acceptable records involving six birds, all in late September and early October; Birds Korea archives), and Hong Kong (first in 2008; N. Moores in litt.). Birds believed to be hybrids between Red-backed and Brown, Turkestan, and Isabelline shrikes have been found on the breeding grounds in the Altai region and on the winter grounds in Africa, the Middle East, and southeast Asia (Kryukov and Gureev 1997, Panov et al. 2011, Pyle et al. 2015). Hybridization between Red-backed and Turkestan shrikes appears to be rela- tively extensive in the breeding-range over- lap zone—between the Caspian Sea and Altai region—and some authors suggest that those two taxa are, in fact, one biological species (cf. Panov et al. 2011). Hybrids be- tween Red-backed and Isabelline Shrikes on the breeding grounds are less common, and those of Red-backed × Brown are thought to be rare (Pyle et al. 2015). Concerning re- cords of shrike hybrids without a specimen, Worfolk (2000) notes that "the situation is extremely complicated and open to differing interpretations," and "the temptation should be resisted to label a 'difficult bird' a hybrid if sandy-gray-brown color than shown by ei- ther Turkestan or Red-backed shrikes—not warm rusty-brown as in the Gambell bird— and they are often unmarked, including the crown as well as the rump and uppertail co - verts. Like Turkestan Shrike, there is often contrast between the duller upperparts and warmer-colored tail in Isabelline, although the contrast is less distinct. Isabelline Shrike typically shows a weaker face pattern than does Turkestan and Red-backed shrikes, and it lacks a contrasting gray nape. The sides and flanks, and sometimes the auriculars, are variably washed in buff or orange-buff, whether or not they are vermiculated on the sides. If vermiculations are present, they tend to be a weaker warm-brown to pale rufous, not dark brown or dark gray. • HYBRIDS: These four species of shrikes are known to hybridize, most extensively between Red-backed and Turkestan shrikes (Pyle et al. 2015). During review of the im- ages, all the authors and external review- ers (e.g., C. Gooddie, L. Svensson, in litt.) concluded that the Gambell shrike showed no features that indicate a hybrid origin. Importantly, we have concluded that wing and tail morphology are perfectly typical of Red-backed Shrike and clearly eliminate Brown Shrike whereas differences in juve- nile and first-fall plumages are again typi- cal of Red-backed Shrike but clearly elimi- nate Turkestan and Isabelline shrikes. We see no reason to suspect genetic influence from any species other than Red-backed Shrike in the Gamnbell bird. See Pyle et al. (2015) for an extensive discussion on hy- brid shrikes including several images each of Red-backed × Turkestan and Red-backed × Brown shrike hybrids. Range and Vagrancy All four species treated in detail here are Noted Palearctic authority Lars Svensson, upon viewing several photos of the Gambell shrike, stated that "…one important character to note [that is] typical for Red-backed is the rufous-tinged ear-coverts (rear part of the mask). The other related shrikes have dark grey or blackish ear-coverts. So, this is a good sign of being a pure Red-backed. Also, the long primary projection with seemingly only p3–p4 [European numbering system for primaries] emarginated is a sure sign for Red-backed. Turkestan Shrike has invariably subtly shorter primary projection than this, and p3–p5 are emarginated. Lastly, the greyish tinge to the nape and sides of the neck is typical only of Red-backed. So, there you are, all traits point unanimously at Red-backed."

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