Nesting by the Eurasian eagle owl (Bubo bubo) in a nest of the whitetailed eagle (Haliaeetus albicilla)

Abstract

Abstract In 2011 and 201 2 two breedings by a pair of Eurasian eagle owls were observed in an old white-tailed eagles’ nest at Blatná Polianka in the Senianske rybníky SPA. The nest was situated in a grey poplar tree 1 5-20 m above the ground in a treebuffer by the rivulet Okna, in open lowland landscape without woodland, just with linear tree vegetation and scattered trees. In 2011 incubation of the clutch was observed and the female was present in the nest even at the end ofApril, when the fledglings were probably already present in the nest, but no more data on their further success were obtained. In 201 2 the pair of Eurasian eagle owls bred in the same nest again, but in May the nest was already abandoned and we suppose predation of the clutch, probably by ravens. This occasion is the third known breeding attempt by the Eurasian eagle owl in a raptor nest built in a tree, and the first known occasion of breeding in a white-tailed eagles’ nest in Slovakia. The obtained data also document the further spreading of the species in the Dolný Zemplín region into unusual habitats of a lowland agricultural landscape with very few trees.