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Characteristics and Range The larger and more northerly of Manitoba's two shrike species, the Northern Shrike nests in the far north and winters in the south of Manitoba. The Northern Shrike has a longer bill with a more prominent hook than the Loggerhead Shrike, a longer tail, and a narrower black facial mask that typically dœs not join across the top of the bill. The two shrike species nonetheless rarely overlap temporally in Manitoba. Until very recently considered conspecific with the Great Gray Shrike (Lanius excubitor) of Europe, the Northern Shrike nests from Labrador to Alaska mostly near the treeline, as well as in eastern Siberia. North American populations winter across southern Canada from Newfoundland to the Alaska Panhandle, south to Pennsylvania and Colorado and occasionally farther south (Paruk et al. 2017). Although a few Northern Shrikes overwinter in southern Manitoba, many others likely pass through briefly (The Birds of Manitoba).

Distribution, Abundance, and Habitat Atlas data present an intriguing picture of the nesting distribution of the Northern Shrike in Manitoba, providing a dozen confirmed breeding records away from Churchill, in areas such as Kasmere Lake, Nueltin Lake, Nejanilini Lake, and Cape Tatnum, where breeding was suspected but not previously confirmed (The Birds of Manitoba). The range across the northern two-thirds of the Taiga Shield & Hudson Plains and the Arctic Plains & Mountains matches that depicted in The Birds of Manitoba, but more intriguing are five possible breeding records in the Boreal Softwood Shield, in the Split Lake to Leaf Rapids general area, and one in the Boreal Taiga Plains ~40 km south of Ponton. The latter is close to a BBS record near the Hargrave River from 2002 and suggests that the Northern Shrike may nest, at least sporadically, well south of the Hudson Bay Lowlands, as discussed in The Birds of Manitoba. Nonetheless, the southernmost confirmed breeding to date is at 56.7ºN along the Hayes River (J. Fried, 2012).

The Northern Shrike is found most commonly along the treeline-tundra transition in Manitoba, where a patchwork of trees and shrubs (including willow and alder swales) is interspersed with open peatlands or in undulating terrain such as around eskers (pers. obs.). Said to avoid dense conifer stands (Paruk et al. 2017), most southern records, such as at Waskaiowaka Lake and near Ponton, were in regenerating burnt areas.

Trends, Conservation, and Recommendations As with other northern species, little is known about the population dynamics of the Northern Shrike. Analyses of CBC data suggested a 1.3% annual decline from 1965 to 2003 range-wide (Niven et al. 2004), and a recent assessment of 14% population decline overall from 1970 to 2014 (Rosenberg et al. 2016). These estimates require substantiation and, to date, almost nothing is known about the mechanisms of decline, or how the species may respond to climate change. The Northern Shrike is now noticeably reduced from numbers recorded in the 1980s in the immediate Churchill area for reasons that remain unclear (R. Koes, pers. obs.). Some authors have argued that human alterations to habitats on the wintering grounds may be affecting the Northern Shrike in a similar way to impacts on the Loggerhead Shrike (see discussion in Paruk et al. 2017). Better monitoring of this and other northern species is highly desirable.

Christian Artuso

Recommended citation: Artuso, C. 2018. Northern Shrike in Artuso, C., A. R. Couturier, K. D. De Smet, R. F. Koes, D. Lepage, J. McCracken, R. D. Mooi, and P. Taylor (eds.). The Atlas of the Breeding Birds of Manitoba, 2010-2014. Bird Studies Canada. Winnipeg, Manitoba http://www.birdatlas.mb.ca/accounts/speciesaccount.jsp?sp=NSHR&lang=en [11 Oct 2024]