OIL-BIRD. 89 



loud hissing noise, and has the same stooping motion of the liead observable in the 

 owls ; it also resembles these birds in its erect carriage, the manner in which it 

 sets out the feathers round the ears and neck, and in tlie power it possesses of 

 turning the head in every direction even over the back, a habit it is constantly 

 practising." 



The Oil-Bird or Guacharo. 



Family StEATORNITHID^. 



Forming a family group by itself, the South American oil-bird (Steatornis 

 caripensis) in external appearance is not very unlike a nightjar ; to which group 

 it also approximates in habits, only coming out to feed in the dusk of the evening. 

 It is, however, more nearly allied to the frog-mouths, having a similar bridged 

 palate, although differing in certain features of the skeleton. The plumage is less 

 soft than in either the goatsuckers or frog-mouths ; while the beak and the form 

 of the wing are not unlike those of the rollers. The tail carries ten feathers, and 

 in the wing the third and fourth primary quills are the longest ; while the naked 

 metatarsus does not exceed the third toe in length. In the skull the basal rostrum 

 carries articular basipterygoid processes. Measuring from 17 to 20 inches in total 

 length, the oil-bird is chestnut-brown in general colour. On the upper-parts the 

 plumage is marked by numerous dark cross-bars ; the median wing-coverts are 

 ornamented with large white spots, similar spots also occurring on the lateral 

 upper tail-coverts ; while the under surface is pale chestnut, with a greyish tinge, 

 each feather being marked with three rhomboidal spots of wliite bordered with black. 

 The beak is chocolate -brown; the feet are flesh-coloured, with a violet tinge; 

 the claws are grey ; and the iris of the eye is black with a narrow dark brown 

 ring. The gaucharo is principally known as an inhabitant of the island of Trinidad, 

 where it frequents certain caves, building therein huge nests, having the appearance 

 of large cheeses. The popular name of oil-bird is derived on account of the peculiar 

 covering of the nestlings, which are simply masses of yellow fat. Numbers of the 

 stones of a fruit upon which these birds apparently feed strew the floor of the 

 caves where they dwell. Elsewhere local, the oil-bird is found not only in Trinidad, 

 but also from Guiana and Venezuela to Ecuador and Peru, occurring in the latter 

 countries in valleys at an elevation of some seven thousand feet. In the Tatora 

 district of Peru there are several caverns, situated in a very wild country, clad 

 from the base to the summit of the liills with (k^nse vii-gin forest, frequented by 

 these birds. According to Dr. Stolzmann, if a gun be flred, or any otlier loud noise 

 made near these caverns, tlie birds quit their retreats in the nooks and crannies, 

 flying to tlie roof with piercing cries ; and the only way to obtain specimens is to 

 fire at random in the darkness. This, howe\'er, is hapliazard work ; and in the 

 Ninabamba cavern only eleven birds were killed in return for sixty shots. When 

 the birds are tired out, they gradually retire to theii- hiding-places, from which no 

 amount of firing or shouting will induce them to again emerge. AVhen midisturbed, 

 the guacharos quit their retreats as the sun is setting, to fly about the forest ; some 

 of them rising to a considerable elevation, apparently in pursuit of moths. Their 



