SEASONAL DYNAMICS OF THE DIET OF IMPERIAL EAGLES (<i>AQUILA HELIACA</i>, ACCIPITRIDAE, ACCIPITRIFORMES) IN THE LEFT-BANK MIDDLE VOLGA REGION

Abstract

The seasonal and between-year dynamics in the diet of a pair of Imperial eagles (Aquila heliaca) were observed at a nesting site on the left bank of Volga River in the Ulyanovsk Region, European Russia. The research covered three seasons (2019–2021) using an autonomous video surveillance system. During the research period, 555 prey objects brought by eagles to the nest were identified, these representing 30 taxa of wild vertebrates and four species of domestic animals, all from four vertebrate classes. The predominant prey objects were the Russet ground squirrel (Spermophilus major) (35%), the Rock pigeon (Columba livia) (22%), and the Common hamster (Cricetus cricetus) (14%). Rodents prevailed in nutrition during nest construction (April), hatching (May), and at the initial stages of feeding the chick(s) (June–July). The proportion of pigeons and corvines increased significantly in nutrition during the feeding period of grown-up chicks and fledglings (August–September). Raising two chicks compared to one chick led to an average of 1.5 times increase in food intake, mainly due to rodents.