6 Bulletin American Museum of Natural History. [Vol. XXXVI, 



altitude, as well as many field-notes on distribution.^ To these data the 

 writer can add information gained on two expeditions which have led 

 him across the three ranges of the Colombian Andes, from Buenaventura 

 on the Pacific coast to Villavicencio at the eastern base of the Eastern 

 Andes. Not only does a field experience acquaint one with the country, 

 and all that such personally acquired knowledge implies, but it gives one a 

 supply of negative facts which the most extensive collections cannot fur- 

 nish. While specimens show where a species does occur, they fail to tell 

 where it does not occur, and the latter fact is quite as important as the 

 former. But when one is reasonably familiar with the appearance, espe- 

 cially in life, of the birds of a country, not only the presence but also the 

 absence of the more common or conspicuous species is noted. The alti- 

 tudinal ranges of those most easily observed can be determined with more 

 or less accuracy even from horseback as one travels slowly through the 

 mountains. CUmbing to the summit of ridge after ridge, and descending 

 to the floor of the valleys between them, species appear and disappear 

 at certain altitudes with a regularity which enables one to predict with 

 more or less certainty when they will be found and when lost. 



Satisfactory determination of out Colombian specimens, and a true 

 conception of the limits of those faunal areas lying only partly in Colombia 

 required field-work in contiguous regions. Richardson, was, therefore, 

 despatched to Ecuador where he collected some 4000 specimens, while with 

 Anthony and Ball he secured 1800 specimens in eastern Panama. The Smith 

 collection of birds from the Santa Marta region has also been of great 

 service for comparison with our material from other parts of Colombia. 



The routes followed by our eight expeditions, and the localities at which 

 we, as well as others, have collected, are shown on the map accompanying 

 our Gazeteer of Colombian collecting stations; while full itineraries of each 

 expedition are given beyond. 



It will be observed that our work has been restricted to what may be 

 termed Andean Colombia. We have not attempted to penetrate the 

 Amazonian forests beyond the upper Caqueta, or to explore the llanos 

 east of Villavicencio. The uniformity of environmental conditions to the 

 eastward of these points, in connection with our knowledge of Amazonian 

 and Orinocan bird-life, warrant the belief that we should not find eastern 

 Colombia to possess any marked faunal characteristics not shown by ad- 

 joining regions in the same zones. 



The Sierras of the upper Uaupes and upper Inrida doubtless ofier 

 habitats not afforded by the country from which they rise, but the explora- 

 tions of Rice fail to show a higher altitude in these mountains than 2850 



' Cf. BuU. A. M. N. H.. XXXI, 1912, p. 139. 



