Data on the Trophic Spectrum of Young Imperial Eagles (Aquila heliaca Savigny, 1809) in South Bulgaria

The current publication presents the results of a research on the food spectrum of young Imperial eagles (juvennes, immaturus) (Aquila heliaca, SAVIGNY, 1809) in South Bulgaria. Dispersal sites and temporary settlement areas were identified tracking two young eagles marked with radio-transmitters. The birds were tagged in 2007 by the team of Green Balkans Federation. The feeding and behaviour of over 20 young Imperial eagles was observed in a total of 6 regions, including vulture feeding sites. A total of 32 pellets were collected from the trees used by those birds for roosting. Thus the feeding spectrum of young imperial eagles in their roaming period just after fledgling was identified. A total of 13 feeding components, comprising 101 specimens were identified. These were mainly small mammals, dominated by на (Microtus arvalis, P. - complex) (n = 56 specimens, 55,45% and significant presence of House mouse (Mus musculus, L.) ? 18 specimens or 17,82 %). The observations prove the presence of carcass among the food items taken by the wintering eagles and the particular use of the existing artificial feeding sites for vultures. The study proves the food opportunism of the species.