Attributes / relations provided by
♦ ¹Diving behavior of blue-footed boobies Sula nebouxii in northern Peru in relation to sex, body size and prey type, Carlos B. Zavalaga, Silvano Benvenuti, Luigi Dall’Antonia, Steven D. Emslie, MARINE ECOLOGY PROGRESS SERIES 336: 291–303, 2007
♦ 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.