We describe, for the first time, the rattling call of the Crested Honey Buzzard Pernis ptilorhynchus. This was previously considered to be a unique vocalization of European Honey Buzzard Pernis apivorus; however, we detected this series of rapidly repeated notes given by an adult female, a second-year, a juvenile and a nestling Crested Honey Buzzard. The rattling calls appeared to be given at times of great excitement, such as to an approaching intruder, mate or parent at the nest, or to a familiar person who usually gave food in the case of captive individuals. The rattling call of an adult female Crested Honey Buzzard at the nest was at a frequency of 2.12 (s.d.±0.07) kHz, and lasted 141 (s.d.±18) ms, which was higher and longer than in European Honey Buzzard.