The common redstart (Phoenicurus phoenicurus), or often simply redstart, is a small passerine bird in the genus Phoenicurus , and is an Old World flycatcher (family Muscicapidae)
The Common Redstart shows some affinity to the European Robin in many of its habits and actions. It has the same general carriage, and chat-like behaviour, and is the same length at 13–14.5 cm long but slightly slimmer and not quite as heavy, weighing 11–23 g. The orange-red tail, from which it and other redstarts get their names (“start” is an old word for “tail”), is frequently quivered. The male in summer has a slate-grey head and upperparts, except the rump and tail, which, like the flanks, underwing coverts and axillaries are orange-chestnut. The forehead is white; the sides of the face and throat are black. The two central tail feathers are dark brown, the other tail feathers bright orange-red. The female is grey-brown above and buff-white or light orange below.
Common Redstarts are sometimes parasitised by common cuckoos. Surprisingly, redstart chicks did not suffer from sharing the nest with a cuckoo chick. The presence of a cuckoo might even be beneficial for the nestlings. The large size of the cuckoo chick affects the thermoregulation in the nest. In some sense, the cuckoo chick is ‘brooding’ the redstart nestlings. Moreover, food provision might be better for redstart chicks in a mixed brood.