Some Aspects of the Nest Etology of the Eastern Imperial Eagle (Aquila heliaca) (Aves: Accipitridae) in Sakar Mountain

A survey was carried out for studying some aspects of nest etology of the eastern imperial eagle (Aquila heliaca Savigni, 1809) in Sakar Mountain. The aim of the survey was to determine apportionment of the parental care between partners in the pair. Incubation in the both studied pairs was taken mainly by the female bird, which incubated 90.8% of the time in one of the pairs corresponding to 94.1% in the other one. Male contributed significantly in food provisioning, supplying 59.2% of the food in one of the pairs and 58.3% in the second one. The survey shows similar results as obtained for the Spanish imperial eagle (A. adalberti). This is the first survey done regarding to distribution of parental care between sexes in the eastern imperial eagle in Bulgaria.