M. Humboldt on the Great Cavern of the Giiacharo. 87 
in^ the pine forests of the north, live in society, and construct 
their nests upon trees, the tops of which touch each other. The 
shrill and piercing cries of the guacharoes strike upon the vaults 
of the rocks, and are repeated by the echo in the depth of the 
cavern. The Indians shewed us the nests of these birds, by 
fixing torches to the end of a long pole. These nests were fifty 
or sixty feet high above our heads, in holes in the shape of fun- 
nels, with which the roof of the grotto is pierced like a sieve. 
The noise increased as we advanced, and the birds were affright- 
ed by the light of the torches of copal. When this noise ceased 
around us, we heard at a distance the plaintive cries of the birds 
roosting in other ramifications of the cavern. It seemed as if 
these bands answered each other alternately. 
The Indians enter into the Cueva del Guacharo once a- 
year, near midsummer, armed with poles, by means of which 
they destroy the greater part of the nests. At this season seve- ' 
ral thousands of birds are killed ; and the old ones, as if to de- 
fend their brood, hover around the heads of the Indians, uttering 
terrible cries. The young, which fall to the ground, are open- 
ed on the spot. Their peritoneum is extremely loaded with fat, 
and a layer of fat reaches from the abdomen to the anus, form- 
ing a kind of cushion between the legs of the bird. This quan- 
tity of fat in frugiferous animals, not exposed to the light, and 
exerting very little muscular motion, reminds us of what has 
been long since observed in the fattening of geese and oxen. It 
is well known how favourable darkness and repose are to this pro- 
cess. The nocturnal birds of Europe are lean, because, instead 
of feeding on fruits like the guacharo, they live on the scanty pro- 
duce of th^ir prey. At the period which is commonly called at 
Caripe the ml harvest^ the Indians build huts with palm leaves, 
near the entrance, and even in the porch of the cavern. Of 
these we still saw some remains. There, with a fire of brush- 
wood, they melt in pots of clay the fat of the young birds just 
killed. This fat is known by the name of butter or oil ( man- 
teca or aceite) of the guacharo. It is half liquid, transparent, 
without smell, and so pure that it may be kept above a year 
without becoming rancid. At the convent of Caripe no other 
oil is used in the kitchen of the monks but that of the cavern ; 
and we never observed, that it gave the aliments a disagreeable 
taste or smell. 
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