2 54 Naturalist in La Plata. 
formed daily, the birds beginning to assemble at 
about nine or ten o’clock in the morning, their 
number increasing through the day until it reaches 
its maximum between two and four o’clock in the 
afternoon, after which it begins to diminish, each 
bird going off to its customary shelter or dwelling- 
place. Mr. Bates, who first described these wander- 
ing bands, says that he could always find the 
particular band belonging to a district any day he 
wished, for when he failed to meet with it in one 
part of the forest he would try other paths, until he 
eventually found it. The great Amazonian forests, 
he tells us, appear strangely silent and devoid of 
bird life, and it is possible to ramble about for 
whole days without seeing or hearing birds. But 
now and then the surrounding trees and bushes 
appear suddenly swarming with them. The bust- 
ling crowd loses no time, and, always moving in 
concert, each bird is occupied on its own account 
in searching bark, or leaf, or twig. In a few 
moments the host is gone, and the forest path 
remains deserted and silent as before.” Stolzmann, 
who observed them in Peru, says that the sound 
caused by the busy crowd searching through the 
foliage, and the falling of dead leaves and twigs, 
resembles that produced by a shower of rain. The 
Indians of the Amazons, Mr. Bates writes, have a 
curious belief to explain these bird armies ; they 
say that the Papa-uira, supposed to be a small grey 
bird, fascinates all the others, and leads them on a 
weary perpetual dance through the forest. It seems 
very wonderful that birds, at other times solitary, 
should thus combine daily in large numbers, includ- 
