Siberian Nuthatch Sitta arctica is split from Eurasian Nuthatch S. europaea (Clements 2007:529–530)

Summary: Eastern Russia now has its own endemic species of nuthatch, the Siberian Nuthatch. This species may co-occur with local forms of Eurasian Nuthatch and they may even flock together in the non-breeding season.

Details: Just one of several taxa originally described as full species that have long been united in Sitta europaea (e.g., Greenway 1967), S. arctica was not even described to science until 1907. Although it has numerous differences in details of plumage and proportions, these are not visually striking when compared with the vast variation exhibited by the S. europaea complex. However, Sitta arctica was found to be highly distinct in an mtDNA study (Zink et al. 2006), so much so that it was used to root the trees of S. europaea in Hung et al. (2012). It is evidently sympatric with S. europaea, and said to have very different vocalizations (Red’kin and Konavalova 2006). It was thus split by several sources including Dickinson and Christidis (2014) and del Hoyo and Collar (2016), and followed by Gill and Wright (2008, IOC v.1.6), and now WGAC and Clements et al. (2023). A recent multi-locus phylogeny (Päckert et al. 2020) confirms that S. arctica is basal to the large clade comprising most of the Asian Sitta species, and thus species status is unequivocally upheld.