BIRD LIFE IN THE UEUBAMBA VALLEY OF PERU. 15 



Amazonian drainage. The ascent from the Titicaca Basin is very 

 gradual; the descent toward Cuzco is more rapid, the last 30 kilo- 

 meters of the ascent giving an increase of only 412 meters as com- 

 pared with a fall of 647 meters for the first 30 kilometers beyond the 

 divide. 



Tiie Urubamba River has its origin in the marshes and lagoons 

 which lie immediately below the Pass. (PI. 2.) 



While at and near La Raya, November 9-25, 1915, Heller collected 

 only mammals and our collection of birds from that place was made 

 by Watkins. Beyond such widely distributed species as Nycticorax 

 naevius, Falco fusco-caerulescens, BracJiyspiza capensis peruviana and 

 some others, the species secured are characteristic of the Puna. The 

 following description of the region was written by Heller: 



La Raya Pass is an open, level-floored valley, grass-covered and dotted by small 

 lagoons and marshy streams. Bounding the valley floor are rounded, grass-covered 

 hills, and in places rocky ridges rising to a height of 2,000 or 3,000 feet. To the east 

 of the Pass a view of snow-capped peaks, their sides furrowed by glaciers, may be 

 obtained, but to the west the ridges are lower and without permanent enow fields. 



The temperature here was decidedly cool, or even bitter, during the day when the 

 wind was blowing, and at night there was hoar frost. During our stay in November 

 we were visited every evening about sunset by a violent thundershower of an hour's 

 duration. The storm usually resolved itself into a hail or sleet affair accompanied 

 by a heavy artillery of thunder and flashes of lightning which swept over the land- 

 scape until dark. The days were bright with sunshine and as a rule calm, but the 

 temperature was always bracing, although the sun was powerful enough to melt the 

 light coating of sleet of the previous night's storm. 



The region of La Raya is quite treeless and to all appearances bushless as well. 

 Tussocks of coarse bunch grass with sharply spiked blades are the all-pervading floral 

 feature. Other species of more tender grasses, on which the flocks of llamas and 

 alpacas feed, grow with these, but they are much less conspicuous. Matlike clusters 

 of small brilliantly green herbs grow in the damp meadows, but such are quite grass- 

 like in general appearance. On the rocky hillsides amid the shingle and gravel are 

 found clumps of a yucca or Spanish bayonet with whorls of gray spiny leaves and 

 tall dried flower stalks of past seasons still standing. A cactus, a small white silky 

 cereus, grows sparingly at this altitude. One of the few flowering plants seen here 

 was a nettle-leaved herb bearing showy, poppy-red flowers. A few inconspicuous 

 flowers of anemone-like appearance were seen in the meadows. High up on the 

 hillsides a few verdant bushes were encountered, but they were very local in dis- 

 tribution. 



Watkins' Expedition, April 3-13, 1917, 142 specimens of 40 species. 



Pisac (altitude 10,060 feet, junction of arid Temperate and Puna 

 Zones). — A town in the Urubamba Valley about 7 miles northeast 

 of Cuzco. 



Watkins' Expedition, April 17-20, 1916, 65 specimens of 23 species. 



Calca (altitude 9,957 feet, junction of arid Temperate and Puna 

 Zones). — A town in the Urubamba Valley near Urubamba with essen- 

 tially the fauna of the Cuzco district. 



Watkins' Expedition, April 21-25, 1917, 34 specimens of 23 species. 



