GUACHARO (said to be an obsolete Spanish word signifying one that cries, moans or laments loudly), the Spanish-American name of what English writers call the oil-bird, the Steatornis caripensis of ornithologists, a very remarkable bird, first described by Alexander von Humboldt (Voy. aux rég. équinoxiales i. 413, Eng. trans. iii. 119; Obs. Zoologie ii. 141, pl. xliv.) from his own observation and from examples obtained by Aimé J. A. Bonpland, on the visit of those two travellers, in September 1799, to a cave near Caripé (at that time a monastery of Aragonese Capuchins) some forty miles S.E. of Cumaná on the northern coast of South America. A few years later it was discovered, says Latham (Gen. Hist. Birds, 1823, vii. 365), to inhabit Trinidad, where it appears to bear the name of Diablotin; but by the receipt of specimens procured at Sarayacu in Peru, Cajamarca in the Peruvian Andes, and Antioquia in Colombia (Proc. Zool. Society, 1878, pp. 139, 140; 1879, p. 532), its range has been shown to be much greater than had been supposed. The singularity of its structure, its curious habits, and its peculiar economical value have naturally attracted no little attention from zoologists. First referring it to the genus Caprimulgus, its original describer soon saw that it was no true goatsucker. It was subsequently separated as forming a subfamily, and has at last been regarded as the type of a distinct family, Steatornithidae—a view which, though not put forth till 1870 (Zool. Record, vi. 67), seems now to be generally deemed correct. Its systematic position, however, can scarcely be considered settled, for though on the whole its predominating alliance may be with the Caprimulgidae, nearly as much affinity may be traced to the Strigidae, while it possesses some characters in which it differs from both (Proc. Zool. Society, 1873, pp. 526-535). About as big as a crow, its plumage exhibits the blended tints of chocolate-colour and grey, barred and pencilled with dark-brown or black, and spotted in places with white, that prevail in the two families just named. The beak is hard, strong and deeply notched, the nostrils are prominent, and the gape is furnished with twelve long hairs on each side. The legs and toes are comparatively feeble, but the wings are large. In habits the guacharo is wholly nocturnal, slumbering by day in deep and dark caverns which it frequents in vast numbers. Towards evening it arouses itself, and, with croaking and clattering which has been likened to that of castanets, it approaches the exit of its retreat, whence at nightfall it issues in search of its food, which, so far as is known, consists entirely of oily nuts or fruits, belonging especially to the genera Achras, Aiphanas, Laurus and Psichotria, some of them sought, it would seem, at a very great distance, for Funck (Bull. Acad. Sc. Bruxelles xi. pt. 2, pp. 371-377) states that in the stomach of one he obtained at Caripé he found the seed of a tree which he believed did not grow nearer than 80 leagues. The hard, indigestible seed swallowed by the guacharo are found in quantities on the floor and the ledges of the caverns it frequents, where many of them for a time vegetate, the plants thus growing being etiolated from want of light, and, according to travellers, forming a singular feature of the gloomy scene which these places present. The guacharo is said to build a bowl-like nest of clay, in which it lays from two to four white eggs, with a smooth but lustreless surface, resembling those of some owls. The young soon after they are hatched become a perfect mass of fat, and while yet in the nest are sought by the Indians, who at Caripé, and perhaps elsewhere, make a special business of taking them and extracting the oil they contain. This is done about midsummer, when by the aid of torches and long poles many thousands of the young birds are slaughtered, while their parents in alarm and rage hover over the destroyers’ heads, uttering harsh and deafening cries. The grease is melted over fires kindled at the cavern’s mouth, run into earthen pots, and preserved for use in cooking as well as for the lighting of lamps. It is said to be pure and limpid, free from any disagreeable taste or smell, and capable of being kept for a year without turning rancid. In Trinidad the young are esteemed a great delicacy for the table by many, though some persons object to their peculiar scent, which resembles that of a cockroach (Blatta), and consequently refuse to eat them. The old birds also, according to E. C. Taylor (Ibis, 1864, p. 90), have a strong crow-like odour. But one species of the genus Steatornis is known.
In addition to the works above quoted valuable information about this curious bird may be found under the following references: L’Herminier, Ann. Sc. Nat. (1836), p. 60, and Nouv. Ann. Mus. (1838), p. 321; Hautessier, Rev. Zool. (1838), p. 164; J. Müller, Monatsb. Berl. Acad. (1841), p. 172, and Archiv für Anat. (1862), pp. 1-11; des Murs, Rev. zool. (1843), p. 32, and Ool. Orn. pp. 260-263; Blanchard, Ann. Mus. (1859), xi. pl. 4, fig. 30; König-Warthausen, Journ. für Orn. (1868), pp. 384-387; Goering, Vargasia (1869), pp. 124-128; Murie, Ibis (1873), pp. 81-86. (A. N.)
- Not to be confounded with the bird so called in the French Antilles, which is a petrel (Oestrelata).