BIRD LIFE IN THE URUBAMBA VALLEY OF PERU. 27 



In general it may be said that the Tropical, Subtropical, and 

 Temperate Zones of the Urubamba district are essentially the Trop- 

 ical, Subtropical, and Temperate Zones of Colombia; the same 

 altitudinal boundaries and many of the same species being common 

 to both regions. When, however, v/e compare the Para,mo or Puna 

 Zone of the tv/o countries the area occupied by this zone in Peru is 

 so much larger and its distance from the region whence its fauna was 

 presumably derived is so much shorter, that there is a marked 

 difference in the character of its fauna as will be shown beyond. 



TROPICAL ZONE. 



The Tropical Zone is represented in the Urubamba Valley in both 

 its humid and arid phases. The former, characterized by heavy rain- 

 fail and consequently luxuriant forest growth, ascends the valle}^ to 

 the vicinity of Echarati, some 30 miles below Santa Ana. The 

 latter, distinguished by lower rainfall and a xerophytic vegetation 

 of which acacias and cacti are prevailing types, extends up the floor 

 of the valley to about San Miguel Bridge (altitude 6,000 feet), or the 

 lower border of the forests of the Subtropical Zone. 



Our stations in the humid Tropical Zone were Rio Cosireni (alti- 

 tude 3,000 feet) and Rio Comberciato (altitude 1,800-2,000 feet). 

 These were visited only by Heller who secured, as elsewhere men- 

 tioned, 74 specimens of 58 species of which 42, not found elsewhere, 

 are characteristic of the humid tropics. This number includes such 

 typical tropical forms as Tinamus major rujiceps, CryfAurus soui, 

 Penelope jaqua^u, Eurypyga major meridionalis, Capita auratus 

 insperatus, Monasa morpJioeus peruana, Cephalopterus ornitus, 

 Ostinops decumanus maculosus, etc. While the number of species 

 secured obviously represents only a small part of the existing avi- 

 fauna, it is sufficient to determine its faunal attributes. 



It may also be remarked in passing that this small collection 

 illustrates the uniformity of Tropical Zone life where essentially 

 similar conditions exist, all of the genera and 30 of the 42 character- 

 istic species it contains being found in Colombia. 



Our only station in the arid Tropical Zone was Santa Ana, where 

 the hospitality of Senor Duque, rather than the attractions of the 

 fauna, evidently induced Kalinowski as well as the representatives 

 of the Yale University-National Geographic Society to make their 

 headquarters. The Santa Ana Valley is a typical arid pocket such 

 as is found in many places in the Tropical Zone. Though com- 

 pletely isolated from one another, often by wide areas of the humid 

 Tropical Zone, certain species are common to them all, and, as a 

 rule, slight differentiation from type is exhibited. Several sub- 

 species have been described from the Santa Ana Valley, though I 

 do not know that they are restricted to it, but only one species 

 (ThamnopMlus mclanocJirous) appears to be peculiar to this district. 



