Abstract: Here we present a succesful adoption within a taxonomic family but across orders in birds of prey. From 1977 through 2021, we monitored the population of the Eastern Imperial Eagle (Aquila heliaca, hereafter Imperial Eagle) on the territory of the Ponitrie Protected Landscape Area in the Slovakia. The number of pairs gradually increased there and, altogether 15 pairs were monitored each year since 2018. In 2021, we found the Common Buzzard (Buteo buteo) chick in the nest of the Imperial Eagle in the Ipeľská pahorkatina Hills during the regular monitoring of breeding pairs. It is generally the first known documented record of a young Common Buzzard reared by the Imperial Eagle without human intervention. Parental care of the Imperial Eagle adults on the nest is described and possible alternative explanations for this case of adoption are discussed.

Key words: interspecific adoption, nest parasitism, birds of prey, Slovakia