We would like to invite you to visit the website of Igor Karyakin: Russian Birds of Prey Researchers Club. General and some local /map/ information on Short-toed Eagle can be found there:
• Игорь Карякин, 1998 – Змееяд – Пернатые хищники Уральского региона. Соколообразные (Falconiformes) и Совообразные (Strigiformes). Пермь: Центр полевых исследований Союза охраны животных Урала / Социально-экологический союз: 180-189 – 
(Ru).
• Г.П. Дементьев, 1951 – Змееяд (Circaetus gallicus) – Птицы Советского Союза, т.1. – М.: Сов. наука – (Ru).
(the source is a subsection of the site: Publications)
One more general description (Ru) (composed, in this case, by Igor Karyakin) is located in the subsection titled Articles on Species.