298 The Naturalist in La Plata. 



same time an internal note with great vehemence ; 

 and suddenly, as the danger comes nearer, they 

 plunge simultaneously, with a startled cry, into 

 their burrows. But in some curiosity is the 

 strongest emotion ; for, in spite of their fellow's 

 contagious example, and already half down the en- 

 trance, again they start up to scrutinize the stranger, 

 and will then often permit him to walk within five 

 or six paces of them. 



Standing on the mound there is frequently a 

 pair of burrowing owls (Pholeoptynx cunicularia). 

 These birds generally make their own burrows to 

 breed in, or sometimes take possession of one of the 

 lesser outside burrows of the village ; but their 

 favourite residence, when not engaged in tending 

 their eggs or young, is on the vizcachera. Here a 

 pair will sit all day ; and I have often remarked a 

 couple close together on the edge of the burrow ; 

 and when the vizcacha came out in the evening, 

 though but a hand's breadth from them, they did 

 not stir, nor did he notice them, so accustomed are 

 these creatures to each other. Usually a couple of 

 the little burrowing Geositta are also present. They 

 are lively creatures, running with great rapidity 

 about the mound and bare space that surrounds it, 

 suddenly stopping and jerking their tails in a slow 

 deliberate manner, and occasionally uttering their 

 cry, a trill, or series of quick short clear notes, re- 

 sembling somewhat the shrill excessive laughter of 

 a child. Among the grave, stationary vizcachas, of 

 which they take no heed, perhaps half a dozen or 

 more little swallows (Atticora cyanoleuca) are seen, 

 now clinging altogether to the bank-like entrance 



