Taxonomy
This species was first described by Linnaeus in his Systema naturae in 1758 as Parus caeruleus.
Most authorities retain Cyanistes as a subgenus of Parus, but the British Ornithologists' Union treats Cyanistes as a distinct genus. This is supported by mtDNA cytochrome b sequence analysis which suggests that Cyanistes is not only distinct, but not close to other tits.
Read more about this topic: Blue Tit