THE BIRDS OF THE SANTA MARTA REGION OF 

 COLOMBIA: A STUDY IN ALTITUDINAL 

 DISTRIBUTOR 



By W. E. Clyde Todd and M. A. Carriker, Jr. 

 (Plates I— IX.) 



Introduction. 



The concerted attack of late being made by ornithologists upon South 

 America is yielding results of great scientific interest and value, and 

 bids fair to give us in due course as good a knowledge of the avifauna 

 of the " Great Bird Continent " as we possess of any other of the 

 primary zoological regions of the earth's surface. Unlike much of 

 the work of the last century, which had for its principal aim the dis- 

 covery and description of new species, the ornithological exploration of 

 today is being carried on more along faunal lines, and directed toward 

 a different end, namely, the discovery of the geographical relations of 

 species and groups. Whereas systematic ornithology is concerned 

 with the placing of the various species of birds in their proper and 

 natural position r in the avian series, and with the working out of their 

 genetic relationships, regional ornithology seeks to discover the sig- 

 nificance of the association of such species as they exist in nature, 

 how this association was brought about, and the laws which govern 

 their distribution in the present and their dispersion in the past. Not 

 that these two lines of research are independent of each other ; they 

 are, indeed, closely related problems, in which investigation often 

 meets on common ground and leads to mutually complementary results. 



South America, with its great diversity of physical and climatic 

 conditions, its lofty mountains and wide river valleys, its extensive 

 forests, marshes, and open plains, presents an unusually inviting field 

 for zoogeographical studies of this kind, the more so as this phase of 

 the subject has received so little attention hitherto, and until very 

 recently has been known only in its broad general outlines. But the 

 field to be covered is so vast, and much of it still so imperfectly ex- 

 plored, that as yet there has been little time and opportunity in many 



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