The\u00a0Eurasian blue tit is a small\u00a0passerine\u00a0bird\u00a0in the\u00a0tit\u00a0family\u00a0Paridae. The bird is easily recognisable by its blue and yellow plumage, but various authorities dispute their scientific classification.<\/p>\n
Eurasian blue tits, usually\u00a0resident\u00a0and\u00a0non-migratory\u00a0birds, are widespread and a common resident breeder throughout temperate and subarctic\u00a0Europe\u00a0and western\u00a0Asia\u00a0in 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\u00a0great tit.<\/p>\n
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 skill, as they can cling to the outermost branches and hang upside down when looking for food.<\/p>\n
The Eurasian blue tit is usually 12 centimetres (4.7 in) long with a wingspan of 18 centimetres (7.1 in) for all genders, and weighs about 11 grams (0.39 oz). A typical Eurasian blue tit has an azure blue crown and dark blue line passing through the eye, and encircling the white cheeks to the chin, giving the bird a very distinctive appearance. The forehead and a bar on the wing are white. The nape, wings and tail are blue and the back is yellowish green. The underparts is mostly sulphur-yellow with a dark line down the abdomen – the yellowness is indicative of the number of yellowy-green caterpillars eaten, due to high levels of carotene pigments in the diet. The bill is black, the legs bluish grey, and the irides dark brown. The sexes are similar, but under ultraviolet light, males have a brighter blue crown. Young blue tits are noticeably more yellow.<\/p>\n