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.
THE TRUE DWARF OWL SWALLOW.
The TRUE DWARF OWL SWALLOW (Ægotheles Novæ Hollandiæ) is about nine inches and a quarter long, and above twelve in breadth. The upper part of the body is dark brown, streaked with white; the entire under surface, a spot near the eye, and two sickle-shaped lines, the one on the neck and the other at the back of the head, are grey, dotted with black and reddish yellow; the anterior quills are brown, spotted with light brown and grey on the inner web; the tail is dark brown, regularly striped with grey, and dotted with black; the iris is nut-brown; the feet of a pink flesh-colour. The sexes are alike in size, and similarly tinted, but the plumage of the young is darker than that of the adult bird. Gould tells us that this species lives and breeds in all woodland districts throughout Southern Australia and Tasmania, and that it also frequents the shrubs and bushes upon the coast. Its flight is direct and slow, and, when perched, its attitudes resemble those of an Owl; like that bird, if disturbed, it turns its head rapidly in all directions, and emits a low, hissing sound. The Dwarf Owl Swallow breeds twice in the year, and deposits its four or five round pure white eggs in the hollows of trees. One strange habit possessed by this bird renders the discovery of its retreat very easy; for no sooner is any unusual sound made in the vicinity of its hole than the active little occupant at once scrambles up to the entrance, and putting out its head, peers around to discover the cause of the disturbance. Should danger seem imminent it at once takes flight, and seeks safety elsewhere; but should nothing alarming be in view, it quietly returns to the bottom of its abode, until again roused by some voice from the outer world.