Holarctic Region: This includes Europe and all of Asia except the 

 tropical southern part. It also includes Africa north of the Sa- 

 hara, the Arctic islands, and North America south to the line of 

 tropical rain-forest in Mexico. 



Ethiopian Region: This is Africa south of the Sahara, and is very well 

 characterized. As here understood, it also includes Madagascar, 

 though Madagascar could well be considered as a separate re- 

 gion. Southern tropical Asia is excluded and placed in another 

 region, the Oriental, though a strong case could be made for 

 including it in the Ethiopian Region. 



Oriental Region: This includes India, the Malay countries, and the 

 East Indian Islands as far as Wallace's Line, which lies between 

 Bali and Lombok. It is not well characterized, compared with 

 the African fauna, and could easily be included as a modified 

 extension of the Ethiopian Region. 



Australian Region: This includes a number of centers of distribution 

 that some workers incline to consider as separate regions; 

 namely, Polynesia, New Zealand, Australia, and Papua. Here 

 they are considered sub-regions. 



Neotropical Region: This includes South and Central America, and 

 forms a very distinct region. The West Indies, though showing a 

 pronounced North American influence, are included. 



In addition, many groups of birds are more widespread, so that their 

 distributions do not fit the above pattern; these include: 



(1) Pan-tropical groups of .sea birds, such as frigate birds, tropic birds, 



and boobies (largely) in most tropical waters; land birds such as 

 parrots, barbets and trogons, found in the tropics of both the Old 

 and New Worlds (but the last two absent in the Australian area). 



(2) Pan-boreal groups in the northern part of the Old and the New 



Worlds, many species with a circumpolar distribution. This is 

 particularly true of the Arctic, where there are no obvious dif- 

 ferences between the New World groups and those of the Old 

 World. 



(3) Pan-Austral groups in the southern part of the southern ocean, 



including the penguins and many petrels and albatrosses, which 



have a widespread distribution in southern oceans around the 



South Pole, ranging northward to varying distances. 



The above cases of wide range include birds that occupy belts of 



habitat around the earth, parallel with the equator. There are also a 



[15] 



