Large seabird of offshore tropical waters around the globe. Adult is mostly white with a black trailing edge to the wings, black tail, and dark mask at base of stout yellow bill. Immature has brown head, neck, and upperparts, sometimes with messy white patches. Immature told from most other boobies by pale yellowish bill and mostly white underwings. Essentially identical to Nazca Booby until at least one year old, when Nazca starts developing orange or pinkish bill color. Nests on islands; very rarely seen from the mainland. Often found with feeding groups of other seabirds such as terns, other boobies, and shearwaters.