Breeds islands in western and central Pacific, from Gulf of Carpentaria, Great Barrier Reef, and Coral Sea islands (northeast of Australia) and north-central Bismarck Archipelago eastward through Northwestern Hawaiian Islands and Pitcairn group.
ridgwayi
Breeds far eastern Pacific islands on Revillagigedo, Cocos, Galapagos, and islands just off Ecuadorian coast.
nicolli
Breeds Trindade and Martím Vaz islands (off eastern Brazil); ranges to Brazil.
aldabrensis
Breeds western Indian Ocean islands on Europa (Mozambique Channel), Aldabra and Cosmoledo (Seychelles), and St. Brandon (Mascarenes).
minor
Breeds Chagos, Cocos (Keeling), and Christmas islands (east-central Indian Ocean), Flores and Banda Sea islands (southern Indonesia), Paracel Islands (South China Sea, Ashmore Reef (Australia), and other islands off northern Australia.
