The zoogeographic regions used in GRIN are based on Newton (2003. The speciation and biogeography of birds. Academic Press, Amsterdam) and Ferguson-Lees and Christie (2001. Raptors of the world. Houghton Mifflin, Boston).The descriptive text is a synopsis of the extensive information in the former reference. Alternative names are shown in parentheses.

Afrotropical (Ethiopian): Africa south of the Sahara and Indian Ocean islands Madagascar, Comoro Islands, Seychelles, and Mascarene Islands). Latitudes 20°N to 35°S. Total area ~21 million km².

Australasian: Australia, New Guinea, New Zealand and Pacific Islands, including Solomons, New Hebrides, New Caledonia, and Chathams. Total area ~8.9 million km².

Indomalayan (Oriental): Southeast Asia and adjacent islands south of the Himalayas though the Indonesian Archipelago, Philippines, and Borneo to "Wallace's Line" between Bali and Lombok. Total area ~9.6 million km².

Nearctic: North America, Mexico north of the tropics, and Greenland. Longitudes 168°W to 15°W; latitudes ~20°N to 85°N. Total area ~21 million km²

Neotropical: Tropical Mexico, Central America, South America and adjacent islands (Galapagos, Falklands), and the West Indies. Longitudes 112°W to 35°W; latitudes 20°N to 57°S. Total area ~18.2 million km².

Oceanian (Pacific): Various Pacific Ocean islands (principally Micronesia, Melanesia, Polynesia, and Hawaiian Islands). Total area ~166 million km² (land area 46,632 million km²).

Palearctic: All of Europe, Africa north of the Sahara, and Asia north of the Himalayas. Longitudes 10°W to 170°W; latitudes 25°N to 80°N. Total area ~46 million km²