 However, Clark (1999) suggested that these alleged hybridization events may have instead resulted from misidentification of juvenile or subadult black-chested snake eagles as adults of other species.A molecular phylogenetic analysis based on two mitochondrial genes and one nuclear intron showed that the "Circaetus" snake eagles form a monophyletic group that is sister to the Old World vulture group, Aegypiinae.This study also suggested that the black-chested snake eagle was more closely related to the brown snake eagle ("Circaetus cinereus") than to the short-toed snake eagle, supporting its taxonomic recognition as a separate species.