The OIL BIRD (_Steatornis Caripensis_) has hitherto been classed among
the Goatsuckers, but it differs so essentially from any other member of
that family in its mode of life, that we have decided upon describing it
entirely apart. The body of this remarkable species is slender, the head
flat and broad; the wing, in which the third and fourth quills exceed
the rest in length, though long and pointed, does not extend as far as
the extremity of the well-developed tail. The beak is broad at its base,
compressed in the middle, and terminates in a hook; its tip, moreover, is
furnished with two denticulations; the gape extends to the eyes, but the
lower mandible is feeble and considerably shorter than the upper part of
the beak. The feet are so small as to be almost useless upon the ground:
their soles are callous, and the tarsi without feathers; the front toes
are all of equal size, entirely unconnected, and the short hinder toe is
reversible. The plumage is extremely soft, almost silky, and the region
of the beak is overgrown with long bristles; the large eyes are protected
by heavy lids covered with long hairs. The gullet is not dilated into a
crop, and the stomach is very muscular; the entrails are covered with a
fatty layer of such thickness that they may be said to be embedded in
fat. The plumage is of a beautiful reddish brown, deepest in shade upon
the back; the head, breast, belly, wings, and tail are rust-red, marked
with heart-shaped white spots, which are here and there surrounded by
a black line. The eye is blueish black, the beak and feet horn-grey.
The length of this species is about twenty-one inches, and its breadth
about forty-two inches. Humboldt, who discovered this remarkable bird in
1799, found it living in the rocky caverns of Caripe, and more recent
travellers have met with it in the dark clefts and fissures of rocks
among the Andes.
"The Cueva del Guachero, or Cave of the Guacheros," as described by
Humboldt, "is a vast fissure, pierced in the vertical profile of a rock,
facing towards the south; and the rocks which surmount the grotto are
covered with trees of immense height; succulent plants and orchidaceæ
rise in the driest clefts, and plants waving in the wind hang in festoons
at the entrance. Within the cave vegetation continues to the distance of
forty paces. Daylight penetrates far into the grotto, but when the light
begins to fail the hoarse voices of the inhabitants become audible, and
it would be difficult to form an idea of the horrible noise occasioned
by thousands of these birds in the dark parts of the cavern. Their
shrill and piercing cries strike upon the vaults in the rocks, and are
repeated by the subterranean echoes. The Indians showed us the nests of
the Guacheros by fixing a torch to a long pole; these nests were fifty or
sixty feet above our heads, in holes of the shape of funnels, with which
the roof of the grotto is pierced like a sieve. The noise increased as we
advanced, the birds becoming scared by the torches we carried, but when
the din somewhat abated, immediately around us we heard at a distance the
plaintive cries of others at roost in the ramifications of the cavern.
It seemed as if different groups answered each other alternately. The
Indians enter the Cueva del Guachero once a year, near Midsummer. They go
armed with poles, with which they destroy the greater part of the nests.
At that season several thousand birds are killed; and the old ones, as
if to defend their brood, hover over the heads of the Indians, uttering
terrible cries. The young, which fall to the ground, are opened on the
spot. Their peritoneum is found extremely loaded with fat, and a layer
of fat reaches from the abdomen to the vent, forming a kind of fatty
cushion between the legs. At the period commonly called at Caripe the
"oil harvest," the Indians build huts with palm leaves near the entrance
and even in the porch of the cavern, where, with a fire of brushwood,
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 (_mantece_ or _aceite_) of the
Guachero; 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."
Funck, who also visited the cavern above described, states that the
Guacheros leave their nests after darkness has completely closed in, and
that their harsh, raven-like cry may then be heard as they fly about
in quest of food. Fruit forms their usual nourishment, and this they
will swallow, even if as large as a Pigeon's egg; but the seeds and
kernels they reject as indigestible. The nest is constructed of clay,
and the brood consists of from two to four eggs. Grosz also gives an
account very similar to that of Humboldt respecting another stronghold
of the Oil Birds, called the Ravine of Iconongo, that he visited in New
Granada. This extensive nesting-place is about half a mile long, and
from thirty to forty feet broad, and had to be entered by means of a
rope let down from above. Grosz fortunately succeeded in obtaining many
Guacheros, both dead and alive, and made valuable observations relative
to their demeanour and habits. Their movements in the air, he tells us,
are light and rapid, the pinions and tail during their flight being
held fully expanded; upon the ground their gait is extremely awkward,
their feet requiring assistance from the wings, even to sustain the
creeping hobbling motion to which their progress when on _terra firma_
is restricted. Whilst thus attempting to walk the tail is slightly
raised, and the head and neck bent forward in a constant succession of
serpent-like movements, in order to maintain their balance. When perched
they keep the body erect, supporting it slightly upon the wings, and
hang the head droopingly. If much excited whilst in flight, the cry of
the Guachero becomes positively unearthly, so dismally hideous are its
tones. Both parents brood alternately upon the eggs, which, according to
Grosz, are white and pear-shaped. No preparations whatever are made for
the reception of the young family, the eggs being merely deposited in the
clefts of the rocks. The nestlings, when first hatched, are extremely
ugly and uncouth, and completely helpless until they are fully fledged;
so extraordinarily voracious are they that, if other food is not on the
spot, they will fall furiously upon each other, or even seize and drag at
their own feet or wings.
* * * * *
The OWL SWALLOWS (_Podargi_) constitute a family bearing considerable
resemblance to the Night Jars, both in their general appearance and mode
of life. These birds have a slender body and short neck; their head is
broad and flat, their wings short and blunt, their tail long, their tarsi
high and powerful. The beak, which opens farther back than the eyes,
is large, flat at its base, and broader than the brow; the mandibles
are hooked at the tip, of equal length, and smooth at the margin; the
nostrils are situated at the base of the beak, and are almost entirely
concealed beneath the feathers of the forehead. The foot is short, with
three of the toes placed in front, and one pointing directly backwards;
the latter is not reversible. The plumage is soft, and dusky in its
coloration; the region of the beak, and, in some cases, that of the ear,
is covered with a growth of bristles.
Such of these birds as we are at present acquainted with, inhabit the
forests of Southern Asia, as also of New Holland and the neighbouring
islands; but little has as yet been ascertained respecting their general
habits, and we must therefore confine ourselves to the mention of those
species with which we are best acquainted.
* * * * *
The DWARF OWL SWALLOWS (_Ægotheles_), found exclusively in New Holland,
are recognisable by their long but powerful body, nearly round head,
short, rounded wing (in which the second quill exceeds the rest in
length), long, rounded tail, and comparatively high and bare tarsi; the
toes are of equal length and unconnected; the beak is thick, broad,
and compressed at its base, but becomes suddenly narrow towards its
extremity, and terminates in a flat hook; the lower mandible is furnished
with a hollow rim that encloses the curved tip of the upper part of
the beak. The plumage is soft in texture, except around the beak and
in the region of the eyes and brows, these parts being covered with a
bristle-like growth.