References

• Alderfer, Jonathon. 2006. Complete birds of North America. National Geographic Society, Washington D.C., USA
    
• Anderson David J. and P. J. Hodum. 1993. Predator behavior favors clumped nesting in an oceanic seabird. Ecology 74:2462-2464. Ecological Society of America.
   
• Castillo-Guerrero, J.A., E. Mellink, and A. Aguilar. 2005. Bigamy in the Blue-footed Booby and the Brown Booby?. Waterbirds 28:399-401. Universidad Autonoma de Sinaloa; Culiacán, Sinaloa, Mexico.
  
  
• Elphick, C., J.B. Dunning Jr., and D.A. Sibley. 2001. The Sibley guide to bird life & behavior. Alfred A. Knopf, Inc., New York, USA.
   
•  Friesen, V.L. and D.J. Anderson. 1997. Phylogeny and Evolution of the Sulidae (Aves: Pelecaniformes): A Test of Alternative Modes of Speciation. Molecular Phylogenetics and Evolution. 7:252-260. Department of Biology, Queen's University. Kingston, Ontario, Canada.
    
• Kricher, John. 2002. Galapagos. Smithsonian Institution Press. Washington D.C., USA and London, England.
   
•  Palmer, Ralph S. 1962. Handbook of North American birds. Volume 1. Yale University Press, New Haven and London.