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



a certain flower or flowers bloom, and that at other times they are appar- 

 ently wanting. 



Unless, therefore, one specializes on Hummingbirds, learns the periods 

 of inflorescence of their favorite trees and plants, and follows them through- 

 out the year, he will secure only such species as chance to be brought to his 

 attention by the flowers which happen to be in bloom at the time of his 

 presence. 



It is in this family that the native collectors are especially skillful and 

 successful. They know the flowers most attractive to Hummingbirds, 

 where to find them and when they bloom. These they follow at different 

 altitudes throughout the year, and from a suitable vantage point shoot 

 the birds with a pellet of clay from a blow-gun as they poise before a flower. 



It is probable, therefore, that so far as the mere acquisition of specimens 

 is concerned, our knowledge of Colombian Hummimgbirds is reasonably 

 complete. In the restricted Bogota region it is doubtful if any species of 

 Hummimgbirds have escaped the native collector. 



Brabourne and Chubb list one hundred and fifty-eight species of Hum- 

 mingbirds from Colombia, and to this number we have added eleven, chiefly 

 through our explorations in the little-known parts of the country. This 

 makes a total of one hundred and sixty-nine species, of which we have 

 taken only one hundred and five. Comparison of these figures with those 

 of other families gives some most interesting results. Let us take, for 

 example, the Formicariidse or Ant-Thrushes. The species of this family 

 have never especially claimed the attention of the native collector as have 

 the Hummingbirds. They are not in demand by milliners, and their haunts 

 and habits make them difficult to collect with a blow-gun. 



Of this family, Brabourne and Chubb record seventy-five species from 

 Colombia, and to this number we have added forty-nine, making a total 

 of one hundred and twenty-four of which we have taken one hundred and 

 three. Expressed in percentages, our addition to the family of Humming- 

 birds was only seven percent, while to the family of Ant Thrushes we added 

 no less than sixty-five percent! 



Comparison of the proportion of species in each family further shows 

 that, whUe Ant-Thrushes are more diSicult to collect than Hummingbirds, 

 the specialized habits of the latter require that they shall be pursued over 

 a more or less prolonged period; while the former, as permanent residents 

 in one locality, may be taken as well at one time as at another. Thus of 

 the one hundred and sixty-nine species of Hummingbirds, we took only 

 sixty-five percent, but of the one himdred and twenty-four species of Ant- 

 Thrushes we took eighty-three percent. 



