The Red-footed Booby is the nominate member of the genus Sula, i.e., the genus Sula was created, by Carl Linneaus, for the first specimen of the Red-footed Booby collected in 1766 on Barbadoes in the West Indies. The Red-footed Booby is the only polymorphic member of its genus, and among the three subspecies has five distinct adult color morphs; brown, white, black-tailed white, white-tailed brown, white-headed and white-tailed brown morph. For this reason it is common to confuse adults from intermediate morphs and immature white morphs. Juveniles of all morphs are similar: brown with darker primaries, black bills, blackish facial skin, light grey irises and varable feet colour. It is the smalles of the boobies and also the one found further off land. The species also has the largest eyes of its family (Sulidae) which is likely an adaptation for nocturnal feeding on squid and flying-fish.