Nest-site selection, breeding success, and diet of white-tailed eagles (Haliaeetus albicilla) in the Danube Delta, Romania

摘要

The white-tailed eagle is a flagship species of wetland conservation throughout Europe; thus, general conservation efforts targeting this species can provide effective protection for most species occupying similar habitats. The species' breeding ecology is well known in northern and western Europe; however, the locally important Danube Delta population has scarcely been studied. Here, the eagles primarily select tall trees for nesting (mostly willow and white poplar), with most nests built above 15 m. The breeding population is geographically concentrated in the northern and northwestern parts of the delta, most probably because of available nest sites in less-disturbed areas. The population has low breeding success, with nests falling and low productivity of breeding pairs (0.67 fledglings/pair). The diet is diverse, with birds, fish, and mammals being preyed upon. Wildfowl and large cyprinids contribute most to the diet, while corvids and mammals are locally important. Most prey species are common residents, occurring abundantly in the area; thus, food scarcity does not seem to limit the eagle population. To maintain the white-tailed eagle population in the Danube Delta, special effort should be taken for maintaining proper (large) nesting trees or to provide artificial nests in suitable areas.