86 M. Humboldt on the Great Cavern of the Quacharo. 
ty^or forty paces from the entrance. We measured the way by 
means of a cord : and we went on about four hundred and thir- 
ty feet, without being obliged to light our torches. Day-light 
penetrates even into this region, because the grotto forms but 
one single channel, which keeps the same direction from south- 
east to north-west Where the light begins to fail, we heard 
from afar the hoarse sounds of the nocturnal birds, sounds 
which the natives think belong exclusively to those subterrane- 
ous places. 
The guacharo is of the size of our fowls, has the mouth of 
the goatsuckers and procnias, and the port of those vultures, 
the crooked beak of which is surrounded with stiff silky hairs. 
It forms a new genus, very different from the goatsucker by 
the force of its voice, by the considerable strength of its beak, 
containing a double tooth, by its feet without the membranes 
that unite the anterior phalanxes of the claws. It is the first 
example of a nocturnal bird among the passeres dentirostrati. 
In its manners it has analogies both with the goatsuckers and 
the alpine crow. The plumage of the guacharo is of a dark 
bluish-grey, mixed with small streaks and specks of black. 
Large white spots, which have the form of a heart, and which 
are bordered with black, mark the head, the wings, and the 
tail. The eyes of the bird are hurt by the blaze of day ; they 
are blue, and smaller than those of the goatsuckers. The 
spread of the wings, which are composed of seventeen or eighteen 
quill feathers, is three feet and a half. The guacharo quits the 
cavern at night-fall, Especially when the moon shines. It is al- 
most the only frugiferous nocturnal bird that is yet known ; the 
conformation of its feet sufficiently shows, that it does not hunt 
like our owls. It feeds on very hard fruits ; as the nut-cracker 
and pyrrhocorax. The latter nestles also in clefts of rocks, and 
is known under the name of night-crow. The Indians assured 
us, that the guacharo does not pursue either the lamellicornous 
insects, or those phalffinm which serve as food to the goatsuck- 
ers. It is sufficient to compare the beaks of the guacharo and 
goatsucker, to conjecture how much their manners must differ. 
It is difficult to form an idea of the horrible noise occasioned by 
thousands of these birds in the dark part of the cavern, and 
which can only be compared to the croaking of our crows, which, 
