1917.] Chapman, Distribution of BirdAife in Colombia. 163 



Fulica americana columhiana, Ixobrychus exilis bogotensis and Asio 

 flammeus bogotensis are also Savanna forms of presumably northern origin 

 which have reached Colombia under climatic conditions no longer existing, 

 and are now associated there with species of southern origin, which have 

 apparently arrived during prevailing conditions. 



Characteristic forms of the Temperate Zone whose origin is not now 

 determinable, are species of the genus Grallaria, Ochthceca, Diglossa and 

 Buthraupis, while the Hummingbirds, of which we found some sixteen 

 species, are more numerous than the members of any other family. 



The more uniform climatic conditions of higher altitudes, as well as of 

 higher latitudes, tends to create corresponding uniformity in their life. 

 Unlike the zones below it, the Temperate Zone of Colombia cannot be 

 divided into smaller faunal areas. Even when Temperate Zone islands 

 of the same range are as widely separated as are those of the Western Andes, 

 there is striking similarity in their bird-life. Hence we conclude that as 

 with the Subtropical Zone of Colombia and Costa Rica, they were at one 

 time connected, and owe their present isolation to erosion in the interven- 

 ing area. This belief is strengthened when we compare the life of what we 

 believe to be a true "oceanic" Temperate Zone island in the Santa Marta 

 group, with that of the same zone in the Eastern Andes, and find how few 

 Andean species have crossed to the Santa Martan Zone. 



In the Central and Eastern Andes the Temperate Zone is too continuous 

 to permit of isolation with subsequent differentiation. 



In defining the boundaries of the Subtropical Zone we have seen that 

 when the Andean system of Ecuador and southern Colombia develops into 

 three distinct ranges, the Subtropical Zone of the Pacific slope is continued 

 northward in the Western Andes, that of the Amazonian slope in the East- 

 ern Andes, while the Central Andes, having an indirect connection with 

 both Western and Eastern ranges, has received a certain amount of life from 

 each, but has little of its own. 



When, however, we examine the topographical relations of the Temperate 

 Zone, we find that the Central Andes carries a direct northward extension 

 of the great Ecuadorian interandine temperate region, and as such it has 

 some species, particularly at its southern end, unknown elsewhere in Colom- 

 bia. Examples are AruBaretes p. cequatorialis, Conirostrum fraseri, and 

 Urothraupis stolzmani. 



The importance of giving due consider.ation to suitability of haunt in 

 the study of zoogeography, is forcibly illustrated in the Colombian Temper- 

 ate Zone by the bird-life of the Bogota Savanna. 



Apparently no other part of this zone in Colombia possesses the physical 

 characteristics of that area. Though evidently much modified by cultiva- 



