On males the upperparts are paler; the forehead is whiter; the white supercilium is broader; the white on the primaries and secondaries, on the bases of central tail feathers and on the terminal parts of four outer pairs of tail feathers is more extensive, than on excubitor. The white on tertial is well defined. Uppertail coverts are usually white. The underparts are white without dark pattern.
Probably this race breeds in Northern Kazakhstan and Naurzum Reserve. On autumn wanderings and wintering occurs almost throughout, in particular regularly observed in Kurgaldzhino Reserve and Tien Shan highlands (Bolshoye Almatinskoye lake).
"Птицы Казахстана" том 3. "Наука". Алма-Ата, 1970. Gavrilov E. I., Gavrilov A. E. "The Birds of Kazakhstan". Almaty, 2005. Э.И.Гаврилов. "Фауна и распространение птиц Казахстана". Алматы, 1999.