See also:
Motacilla flava Linnaeus, 1758
Motacilla flava beema Sykes, 1832
Motacilla flava thunbergi Billberg, 1828
Motacilla flava zaissanensis Polyakov, 1911
Motacilla flava leucocephala Przevalski, 1887

No Synonyms

Description. Crown, nape and ear coverts are pale-grey, paler than on thunbergi; ear coverts are grey not blackish; the white supercilium is usually well-defined but occasionally absent; the chin and is white, rare yellow. No pale eye-ring.

Distribution. Breeds in Volga-Ural region and occurs elsewhere on migration. On Chokpak Pass migrates 4 April – 18 May and 24 August – 12 September; on Sorbulak lake 6 April – 7 May and 21 August – 1 October.

References

Gavrilov E. I., Gavrilov A. E. "The Birds of Kazakhstan". Almaty, 2005
Э.И.Гаврилов. "Фауна и распространение птиц Казахстана". Алматы, 1999.