The Nazca Booby was thought to be a variation of the masked booby until a 2002 DNA discovery proved otherwise. To the untrained eye, the two do indeed look identical. Both share a sleek build and white feathers with elegant black trim. A closer look will clue the observer into some key difference, most notably the Nazca Booby’s shorter, flatter beak and its larger size. The Nazca Booby embodies Darwin’s competitive theory of evolution, as it is very competitive both within in its own species, with blue-footed and masked boobies, and even within their own families. Nazca boobies practice siblicide by way of a breeding pattern in which mothers lay two eggs and allow the older chick to throw the younger out of the next. This ensures that one will survive in the event that a predator steals one of the eggs.
These nests and the Nazca Boobys that tend to them are mainly found inland on Genovesa Island, and can be found on Espanola and Isabela island as well. There are about 30,000 in the Galapagos and can also be found in on Clipperton Island and off the coast of Baja, California.