There are a number of subspecies of the Black Redstart (Phoenicurus ochruros) which differ mainly in underpart colours of the adult males.
In general, seven subspecies are accepted. 
They can be separated into three species groups:
1. European species (grey-bellied): P. o. gibraltariensis (Europe) and P. o. aterrimus (only Iberian Peninsula and Morocco);
2. West Asian species (red-bellied): P. o. ochruros and P. o. semirufus; and
3. Central and East Asian species (red-bellied): P. o. phoenicuroides, P. o. rufiventris and P. o. xerophilus.

The male European species has a clear pale wing-patch and a blackish-grey belly and undertail. 
The male West Asian species has a weak pale wing-patch and a blackish-grey breast and rufous belly and undertail. 
The male Central and East Asian species is quite similar to the latter species but it has no pale wing-patch and shows more rufous then black on the breast.

The female is grey (western subspecies) to grey-brown (eastern subspecies) and lacks the white wing patch.
One-year-old males are similar to females but blacker.
The whitish wing panel of the western subspecies does not develop until the second year.
Black Redstarts often sit upright and constantly flick their orange-red tail.

A couple of Black Redstarts (P. o. gibraltariensis) was very busy feeding their 2 babies on the balcony of our hotel in Lindau.
Especially, the female (1st & 2nd photo on the left) was doing the feeding. The baby (1st & 2nd photo on the right & 3rd photo) clearly shows its baby plumage (including a short tail). 

1st, 2nd & 3rd photo: A female feeding her young. Lindau, Bavaria, Germany, 11 July 2013
4th photo: A male. Mainau Island (Bodensee), Baden-Württemberg, Germany, 9 July 2013
5th photo: A female. Mayschoss, Rhineland-Palatinate, Germany, 3 May 2022