The blue-footed booby is native to the tropical regions of the Pacific Ocean and is part of the six species of boobies. There are about six thousand blue-footed boobies in the Galapagos, typically nesting on the rocky shores and cliffs of the islands. Half of the world’s population live in the archipelago.
The blue color of the blue-footed booby's webbed feet comes from carotenoid pigments obtained from its diet of fresh fish. Carotenoids act as antioxidants and stimulants for the blue-footed booby's immune function, suggesting that carotenoid pigmentation is an indicator of an individual's immunological state.