Red-tailed Wheatear was split into Persian wheatear (Oenanthe chrysopygia) and Kurdish Wheatear (Oenanthe xanthoprymna) a couple of years back. The sexes are similar in chrysopygia. Here is a juvenile persian wheatear O.Chrysopygia in the left photo while the sexes are similar in O.chrysopygia but they’ll change quiet a bit after the first winter.
Due to further discussions at birdforum and online searches, Nigel Collar split Red tailed wheatear in to two in the Handbook of the Birds of the World Vol. 10 in 2005. It was also split in the Birds of South Asia, by Collar. This also was published in 2005 by Lynx. Search in google indicates that “A treatment previously recommended by Ivanov (1941), Panov (1999) and by the Taxonomic Advisory Committee of the Association of European Rarities Committees (AERC TAC 2003); the Collins Bird Guide (Svensson et. al. 1999) had also suggested that these two taxanomies may be separate species.
At older ages, it was also “split” by de Filippi in 1863 after his visit to Persia.
There has been a lot of sayings that O. cummingi is considered a hybrid of the other two species O. xanthoprymna and O. chrysopygia (X & C) by Eugene McCarthy. Others say O. cummingi and O. hawkeri are subspecies of the split O. xanthoprymna . Also O. chrysopygia Kingi (Hume 1871) may be a subspecies or possibly a hybrid due to further discussions.
Charles Vaurie states that;
“Oenanthe xanthoprymna xanthoprymna Hemprich and Ehrenberg breeds in southwestern Persia along the outer Zagros.
Oenanthe xanthoprymna chrysopygia de Filippi breeds in the inner Zagros in southwestern Persia, and in the northwest, north, south, and southeast; the northeastern population (Khorasan) is intermediate between this race and the following.
Oenanthe xanthoprymna kingi Hume breeds in Afghanistan, in winter in northwestern India south to Kutch.”