The Eurasian blue tit (Cyanistes caeruleus) is a small passerine bird in the tit family, Paridae. It is easily recognisable by its blue and yellow plumage and small size. Eurasian blue tits, usually resident and non-migratory birds, are widespread and a common resident breeder throughout temperate and subarctic Europe and the western Palearctic in deciduous or mixed woodlands with a high proportion of oak. They usually nest in tree holes, although they easily adapt to nest boxes where necessary. Their main rival for nests and in the search for food is the larger and more common great tit. The Eurasian blue tit prefers insects and spiders for its diet. Outside the breeding season, they also eat seeds and other vegetable-based foods. The birds are famed for their acrobatic skills, as they can hold on to the outermost branches of trees and shrubs and hang upside down when looking for food. Taxonomy The Eurasian blue tit was described by Carl Linnaeus in 1758 in the 10th edition of his Systema Naturae under the binomial name Parus caeruleus. Parus is the classical Latin for a tit and caeruleus is the Latin for dark blue or cerulean. Two centuries earlier, before the introduction of the binomial nomenclature, the same Latin name had been used by the Swiss naturalist Conrad Gesner when he described and illustrated the blue tit in his Historiae animalium of 1555. In 2005, analysis of the mtDNA cytochrome b sequences of the Paridae indicated that Cyanistes was an early offshoot from the lineage of other tits, and more accurately regarded as a genus rather than a subgenus of Parus. The current genus name, Cyanistes, is from the Ancient Greek , "dark blue". The African blue tit (Cyanistes teneriffae) was formerly considered conspecific. Subspecies There are currently at least nine recognised subspecies: C. c. caeruleus – (Linnaeus, 1758): the nominate subspecies, occurring in Continental Europe to northern Spain, Sicily, northern Turkey and northern Urals C. c. obscurus – (Pražák, 1894): found in Ireland, Britain and Channel Islands C. c. ogliastrae – (Hartert, 1905): found in Portugal, southern Spain, Corsica and Sardinia C. c. balearicus – (von Jordans, 1913): found on Majorca Island (Balearic Islands) C. c. calamensis – (Parrot, 1908): found in southern Greece, Pelopónnisos, Cyclades, Crete and Rhodes C. c. orientalis – Zarudny & Loudon, 1905: found in southern European Russia (Volga River to central and southern Urals) C. c.