1917.] Chapman, Distribution of Bird-life in Colombia. 3 



Part I. 

 INTRODUCTION. 



Our knowledge of the animal life of regions remote from the older centres 

 of learning has been acquired through essentially similar channels. The 

 casual specimens brought back, in whole or part, as curios by early ex- 

 plorers, missionaries, travelers and adventurers were, in some instances, 

 followed by shipments of the pelage or plumage of those species having a 

 commercial value. Material of this kind was generally collected by natives 

 and was lacking in data. Later came the exploring naturalists and profes- 

 sional collectors. When not members of an expedition designed to enter 

 some hitherto unknown region, they at first found near the pathways of 

 trade vast territories as yet zoologically unknown. It was only when the 

 faunas of the regions reached by these long existing, if little traveled, routes 

 failed to yield further novelties, that naturalists penetrated into less accessible 

 places which, for some reason, had not lured the prospector, trapper or trader. 



These purely natural history expeditions have, as a rule, gone out to 

 discover new species. Collections were made at widely separated localities 

 with the double object of avoiding duplication of material, and of securing 

 forms which had not before been taken. 



As long as large areas remained unexplored it is natural that we should 

 desire a knowledge of their animal life. But having acquired this knowledge, 

 it is also natural that we should wish to solve the problems which arise from 

 its possession. Thus, through the sources mentioned, we now have so 

 complete a knowledge of South American bird-life that it is not probable 

 further'exploration will reveal any considerable number of distinct species. 

 In short, we have now reached that stage in our study of the South American 

 ornis, when, the search for species over, we may attempt to learn something 

 of the. habits, racial variations and geographic distribution of the between 

 four and five thousand birds known to inhabit that country. 



Acting on this belief, the American Museum of Natural History in- 

 augurated in December, 1910, an intensive zoological survey of South 

 America. For the present the work of this survey is restricted to the col- 

 lecting of birds and mammals and of information concerning them and the 

 country they inhabit. Our ultimate object is the discovery of the geo- 

 graphic origin of South American life, but it is understood that this major 

 problem cannot be successfully approached until we have a lar more definite 

 knowledge of faunal areas in South America than exists at present. 



