Attributes / relations provided by
♦ ¹Distribution and foraging behaviour of the Peruvian Booby (Sula variegata) off northern Chile, Katrin Ludynia, Stefan Garthe, Guillermo Luna-Jorquera, Journal of Ornithology (2010) 151:103–111
♦ ²del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona.