298 The Naturalst 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 wil] 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 eges or young, is on the vizcachera. Herea 
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 
