Any of about 11 species of Old World chat-thrushes (see chat) in the genus Phoenicurus (family Turdidae) or about 12 New World species of wood warblers (family Parulidae) of similar appearance and behaviour. Old World redstarts have a red tail, which they constantly flit or shiver. They are about 6 in. (14 cm) long. The male common redstart (P. phoenicurus) is gray, with a black face and throat and reddish breast. New World redstarts (genera Setophaga and Myioborus) are usually strikingly marked with black, white, and red