BIRD LIFE IN" THE UEUBAMBA VALLEY OF PERU. 17 



Straggling willows and alders line the river margins, beneath which are smaller 

 bushes of many sorts, but there are no groves or clump of trees. On the flat land 

 and lower hill-slopes a few stunted pepper trees carry on a brave struggle for exist- 

 ence against the ax of the wood gatherers. 



Much of the valley floor is covered by a growth of composite bushes of the genus 

 Baccharis, which are the chief thicket-forming shrubs. On the drier slopes far above 

 the creek the yucca or Spanish bayonet clings to the gravelly banks, and at rare inter- 

 vals a giant cactus, a species of Cereus, stands conspicvious and grotesque amid the 

 bushes and rocks. The smaller spiny tree cactus is also found here, as well as 

 numerous other spiny bushes, such as the barberry, Berberis Jlexuosa, Colletia spinosa, 

 and Schinus dependens. (PI . 4 .) 



Heller Expedition, late April 14-23, 1915; 34 specimens of 19 

 species. 



OUantaytarabo (altitude 9,300 feet, arid Temperate Zone), — This 

 station lies in the arid Temperate Zone, the bushy and arborescent 

 vegetation found here on the valley floor offering a home for such 

 characteristic species of this zone as AnaereUs Jlavirostris, Saltator 

 nlbociliaris, and Dv/lossa hrunneiventris. Here, as we descended the 

 valley, we found the last evidences of the Puna Zone in Colaptes puna 

 and Cmclodes fuscus rivularis. (PI. 4.) 



jMt. Heller supplies the following notes on this station, at which 

 the Chapman Expedition collected only on July 5 : 



One of the ancient Inca strongholds was the city of Ollantaytambo, situated some 

 10 leagues northwest of Cuzco in the Urubamba Valley at an altitude of 9,300 feet. 

 At tliis point the valley has great depth, the river having cut its way through the 

 eastern cordillera of the Andes. On either side tower great cliffs to a height of 4,000 

 feet or more, their summits splintered into many fantastic-shaped pinnacles. The 

 rOck formation is chiefly a yellowish flinty shale; in the immediate vicinity, but 

 across the river, on the western side of the valley, are areas of reddish granite, black 

 slates, and other rocks. The position of the town was secure against invasion, except 

 along the valley approaches of the Urubamba and the tributary stream of Ollantay- 

 tambo Creek. In the neighborhood of the town the valley floors have been con- 

 verted into great level terraces of a rich, black soil, free of rocks, which is devoted 

 to the cultivation of maize and wheat chiefly. The climate is quite dry, and to pro- 

 vide against crop failures a series of canals for carr^dng water to the fields have been 

 in use here since ancient times. 



Ollantaytambo was our base station, and thither I returned at intervals during my 

 eight months of field work. During April the rainy season draws to a close, rain fall- 

 ing in the night and then only in intermittent showers. May and June are bright, 

 clear months, but July furnishes a few showers, which again give way to a dry season 

 in August and September. Rain in considerable quantities falls in October, and the 

 country under these deluges blossoms verdant as our own spring in the north. We 

 may consider April to May the fall, July midwinter, owing to its greater cold, and 

 October a spring month, to continue the comparison. There are, however, peculiar 

 contradictions in the actions of some cultivated plants. Upon our arrival at Ollan- 

 taytambo in early April the peach and cherry trees were in blossom, as well as bear- 

 ing nearly ripe fruit, apparently making a brave attempt to combine spring and fall. 

 The native mountain-side shrubs, however, did not blossom as a unit until October, 

 when the giant cactus, Cereus, and herbs generally put forth their floral efforts. Some 

 of the native plants, such as the golden-flowered Spanish broom and Stenolobium 

 2787—21 2 



