any of about 11 bird species of the Old World chat-thrush genus Phoenicurus (family Turdidae), or any of a dozen New World birds of similar appearance and behavior; Old World redstarts are known for their shivering tails and flycatcher-like habits; species include the common redstart (P. phoenicurus); New World redstarts are called woodwarblers; species include the common, or American, redstart (Setophaga ruticilla) and the painted redstart (S. picta); tropical forms are the 10 species of Myioborus.