Recent genetic studies of the Great Grey Shrike complex showed that the barred forms of Siberia, the Central Asian mountains, and of Arctic, and boreal North America, are all closely related, but on the other hand rather distant from those living in much of Europe, the Middle East and North Africa. These barred forms are therefore combined here into a separate species, the Northern Shrike.
It is a medium – to short range migrant, known to have straggled to Fenno-Scandia, and may easily be overlooked in autumn when young Great Grey Shrikes look similar!
Mainly moderate clinal variation among birds in taiga belt, but some more abrupt or marked changes in plumage pattern in Far East and in Central Asian mountains. All races are extralimital, and may straggle regularly, to the treated region. Claimed to be an not uncommon vagrant to Ukraine in winter (Taikova & Redkin 2014)
Races of the Northern Shrike:
Lanius borealis sibiricus Bogdanov 1881
Lanius borealis mollis Eversmann 1853 (Lanius borealis funereus Menzbier 1894 )
Lanius borealis borealis Vieillot 1808
Lanius borealis bianchii Hartert 1907
Handbook of Western Palearctic Birds / Volume 2 – Passerines: Flycatchers to Buntings / Hadoram Shrihai & Lars Svensson, 2018. C. Helm / Bloomsbury publishing. 648 pp (Volume 1) and 623 pp (Volume 2). Numerous colour photographs and maps.