The Blue Tit (Cyanistes caeruleus or Parus caeruleus) is a small passerine bird in the tit family Paridae. The bird is easily recognisable by its blue and yellow plumage, but various authorities dispute their scientific classification.Blue tits, usually resident and non-migratory birds, are widespread and a common resident breeder throughout temperate and subarctic Europe and western Asia 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. The main rival for nests and search for food is the much larger Great Tit.The blue tit prefers insects and spiders for their diet. Outside the breeding season, they also eat seeds and other vegetable-based foods. Blue tits are famed for their skill, as they can cling to the outermost branches and hang upside down when looking for food.