The azure tit (Cyanistes cyanus) is a passerine bird in the tit family Paridae. It is a widespread and common resident breeder throughout Russia and central Asia. It is found in temperate and subarctic deciduous or mixed woodlands, scrub and marshes. It is resident, and most birds do not migrate. It nests in a tree hole, laying about 10 eggs. The bird is a close sitter, hissing and biting when disturbed. Its food is insects and seeds. This 12–13 cm bird is unmistakable. The head, tail corners, wing bars and underparts are white. There is a dark line through the eye, and the upperparts are blue.