1917.] Chapman, Dislrihulion of Bird-life in Colombia. 179 



one of the most interesting and conclusive evidences of the comparatively 

 recent invasion of boreal forms into South America. 



It should be remembered that as ornithologists we are not compiling 

 data merely for other ornithologists, nor, indeed, if this were true, would it be 

 possible for other ornithologists always to examine the specimens on which 

 our conclusions are based. Too often works on geographic distribution bear 

 painful evidence of their author's unfamiliarity with the species on which 

 his theories are raised. It is not to be expected, however, that he should 

 be an expert in every group of animals and I feel it therefore to be the 

 duty of the specialist to employ a nomenclature which will most clearly 

 reveal the known facts in relationship rather than one which, for the sake 

 of a comparatively unimportant consistency, conforms to some arbitrary 

 standard, and emphasizes differences at the expense of resemblances. 



Number of Specia- Included. — The following list contains only species of 

 which, with but few exceptions,' we have collected specimens. It numbers 

 1285 species and subspecies of which forty-five are North American 

 migrants, the remainder being doubtless permanent residents. 



We have done no work on the coasts of Colombiaj and it will be observed 

 that the list includes no marine, and but few littoral species. It might 

 have been materially enlarged by the inclusion of species recorded from 

 Colombia, by other authors, but not secured by us. Since, however, most 

 of these records^ are based on native-made, dataless 'Bogota' skins, it is 

 not believed that the faunal value of this paper would have been increased 

 by their inclusion. 



It may, however, be of interest to state that, roughly speaking, to add 

 to our list of species those recorded by other writers but not obtained by us, 

 would raise the total number of birds known from Colombia (including the 

 Santa Marta region) to about 1700 species and subspecies. 



In making this estimate, I find that our collection of Hummingbirds 

 is more incomplete than that of any other family. There are several reasons 

 for our failure to secure a larger number of the some 170 -odd Hummingbirds 

 known to inhabit Colombia. 



The collecting of Hummingbirds is a special branch of field work. To 

 what extent the wide altitudinal range of many species is governed by the 

 blooming of flowers from which they secure their food, I am unable to say. 

 But it is a fact that certain species are found at a given locality only when 



' For example, the Condor, Roseate Spoonbill, and some others the identity of which was unmis- 

 takable, and under all of which the absence of specimens is acknowledged. 



' This does not relate to the Santa Marta region, which, as elsewhere stated, calls for independent 

 treatment, and which I understand is to be made the subject of an elaborate memoir, by Mr. W. E. C. 

 Todd. 



