Just one more Russian text of 20 years ago on Short-toed Eagles’ nesting in the Vetluga and the Unzha rivers interfluve /map/ is brought to your attention:
• Кузнецов А.В., 1985 – Гнездование змееяда в междуречье Унжи и Ветлуги [Breeding of Short-toed Eagle in the area between the Unzha and Vetluga rivers, Kostroma Region] // Орнитология. М.: Изд-во МГУ, Вып.20. 129-132 (Ru).
This article was published as the result of A. V. Kuznetsov‘s four years’ observations on a pair of the birds in the mentioned region.