There is no flat valley along the river, which is of considerable size, and all cultivation is done on the steep mountainsides. Coca is planted in terraces and occupies the greatest acreage; then there are red bananas, plantains, guavas, and sugar-cane.
The fauna of the country seems to represent a transition zone. There are birds typical of the higher country, and others which are common lower down; also, a number found at approximately this altitude only. Near the house, and on the edge of the banana-plantation, was a tall, isolated tree. Flocks of birds, in their flight from one side of the canyon to the other, would invariably alight in its branches for a few minutes’ rest. There were many brilliantly colored little tanagers (_Tanagra_) which came to the tree in considerable numbers and chirped and quarrelled as they flitted about examining the leaves for insects, or reached out to pick the small fruits with which the tree was covered; one day not less than seven species of these birds visited this resort within a short time.
[Illustration: An Indian hut in the Yungas of Cochabamba.]
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 (_Pyrrhura_) which clung to and crawled up the sides of trees like squirrels; 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 Locotál 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 frequently seen Indians which had been attacked on nose, forehead, and arms.