CROSSING THE BOLIVIAN HIGHLANDS 289 



Giant orioles (Ostinops) were also very plentiful, and 

 travelled in large, noisy flocks. One of the more interesting 

 birds was a species of small, red-tailed parrakeet (Pyrrhurd) 

 which clung to and crawled up the sides of trees like squir- 

 rels; it was almost impossible to see them unless they 

 moved, so well did their coloration, and more particularly 

 their actions, conceal them. 



We had travelled to the Yungas on mules owned by the 

 expedition, and upon our arrival turned them loose to feed 

 as usual. Next morning the animals were in a sorry plight; 

 they had been visited by vampire-bats during the night, 

 and bled so badly that we had to send them back to Lo- 

 cotal without delay. Severe as this attack seemed to be, 

 it was mild compared to what we were to see later on. We 

 discovered clumps of the small bats guilty of the execution 

 spending the days under the roof of our hut, and despatched 

 many of them, but this made no impression whatever upon 

 their vast number. People, also, are bitten on any part 

 of the body which is left exposed at night, and I have fre- 

 quently seen Indians which had been attacked on nose, 

 forehead, and arms. 



After completing our work in the Yungas we returned 

 to Cochabamba in order to await more favorable weather 

 for the trip into the lowlands of eastern Bolivia, and to 

 restock our outfit with articles which had been used, and 

 others which it seemed necessary to acquire for the difficult 

 undertaking ahead. 



After spending several weeks in the vicinity of Cocha- 

 bamba, we made arrangements with the mail-carrier which 

 enabled us to travel jointly to the Chapare. He usually 

 made the trip at six weeks' intervals during the dry sea- 

 son, and, consequently, he knew the trail better than any 

 one else. His peons were also accustomed to the country 

 and knew how to adjust packs so they would meet the 

 varying conditions of the road, which is an "art" that 

 can be learned through long experience only. 



On July 12 we left Cochabamba. Besides my companion 



