Attributes / relations provided by
♦ ¹del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona.
♦ ²Some aspects of the biology of the Black Falcon Falco subniger S. J. S. Debus and J. Olsen, Corella, 2010, 35(1): 29–36