1917.] Chapman, Distribution of Bird-life in Colombia. 205 



Central Andes above the Cauca Valley are true hogotensis. To the north, 

 however, along the Western Andes the Tropical Zone forest of the Pacific 

 slope and Subtropical Zone forests of the summit or both slopes, are con- 

 tinuous, and thus permit the ranges of the two forms to come into actual 

 contact. 



A specimen from an altitude of 2500 feet, on the western slope of the 

 Western Andes above No vita, like the San Antonio specimens, shows an 

 approach in size toward bogotensis, but in color it goes beyond them being 

 in fact so exactly like specimens of bogotensis from the Central Andes that 

 I am wholly unable to discover any color difference between them. This 

 specimen which has been examined by Mr. Ridgway in the course of his 

 studies of Central American birds, is labelled by him C. s. berlepschi, but to 

 my mind it is as satisfactory an intermediate between that race and bogo- 

 tensis as a systematic ornithologist could well ask for. 



Continuing northward we have three specimens of bogotensis from La 

 Frijolera on the lower Cauca River, thus bringing the range of this race to 

 the western slope of the northern Central Andes. 



In Colombia, therefore, bogotensis appears to range from the northern 

 end of the Western Andes, where it intergrades with berlepschi, through the 

 Subtropical Zone of the Central and Eastern Andes to the Tropical Zone 

 at the eastern base of the last-named range. From this point it evidently 

 extends southward to Bolivia whence we have two specimens which seem 

 to be inseparable from Colombian examples. 



This case is particularly interesting since it throws some light on the way 

 in which numerous Amazonian species may have reached the Pacific coast. 

 It is true that we have no specimens from the Temperate Zone, but in a 

 wide-ranging, non-sedentary, adaptable species such as this, it is evident 

 that the narrow strip which in places separates the Subtropical Zone of one 

 slope from the same zone on the opposite slope of a range, is not a sufficient 

 barrier to extension of range. 



Although no form of subvinacea is known from extreme northern Co- 

 lombia where the arid coastal zone does not offer a favorable habitat for 

 this species, the species appears again in northwestern Venezuela as Colu7nba 

 subvinacea zuUcb (Cory, Field Mus. Pub., X, 182, 1915, p. 295) and in extreme 

 northeastern Venezuela as Columba subvinacea peninsularis (Chapman, 

 Bull. A. M. N. H., XXXIV, 1915, p. 366). 



La Frijolera, 3; Salento, 4; La Candela, 3; La Morelia, 1. 



