It is an adult female Pallid, but in a plumage that you don't often see even pictures of.
However, the underwing primary markings clearly show its identity as a Pallid (note pale trailing edge to hand), although the secondaries look quite similar to Montagu's, but this is because of the bird's advanced age. Also the head looks less typical, but again because of its old age, as shown by the bright yellow iris.
Редко птицы до такого возраста в дикой природе доживают, вот и увидеть редко можно.
«Степной лунь (Circus macrourus)» на Яндекс.Фотках