VI PODARGIDAE—STEATORNITHIDAE 419 
Fam. IX. Podargidae.—This group includes some five and 
twenty members of the genera Podargus, Batrachostomus ' (Frog- 
mouth), and <Aegotheles. The first and last occupy Papuasia, 
Tasmania, and Australia, the second ranges from the Himalayas 
to Ceylon, the Philippines, and Malay Islands. 
Fam. X. Steatornithidae—Tlis contains only the curious 
Guacharo, or Oil-bird (Steatornis caripensis) discovered in 1799 
by Humboldt and Bonpland at Caripé in Venezuela, but now 
known to breed also in Colombia, Ecuador, and Peru, as well as 
in Guana and Trinidad. Somewhat intermediate between the 
Owls and the Nightjars, this species is about the size of a Crow, 
with a similar hard beak, hooked and deeply notched, while it has 
twelve long stiff bristles on each side of the gape. The tibiae and 
metatarsl are covered with smooth, flesh-coloured skin, the toes 
being deeply cleft, and not basally united. The tongue is thin and 
triangular, the nostrils have a horny covering, the after-shaft is 
fairly large, while the rest of the structure is mainly Caprimulgine. 
The acuminate and not particularly soft feathers are chocolate and 
grey, with darker barring above, and shew white spots, often sur- 
rounded by black, in various parts. This bird inhabits sea-side or 
mountain-caverns, only issuing forth at dusk to traverse considerable 
distances in search of its food, which consists mainly, if not wholly, 
of fruits. The flight is noiseless, and occasionally high in the air. 
Visitors to the breeding caves are suddenly surrounded by a circling 
crowd of Oil-birds uttering loud croaking or rasping cries, the effect 
being enhanced by the rush of multitudinous wings. A more plain- 
tive note is uttered by individuals at rest. The numerous nests, 
each containing from two to four white or dirt-begrimed eggs, are 
flat circular masses of a clay-like substance, placed on ledges or in 
holes; while the nestlings are considered a table delicacy, though 
said to be scented like cockroaches. The natives systematically kill 
large numbers at certain seasons by knocking them down with 
poles when scared by torchlight, and melt out the abundant fat 
to procure the oil, which gives the bird its name. This oil is 
used for illumination or cooking, and keeps admirably. 
The Sub-Order CypseLI consists of the Families Cypselidae 
or Swifts, and Zvrochilidae or Humming-birds,” which were first 
1 Cf. the French ‘‘ Crapaud-volant’’ or Flying Frog, applied to Nightjars. 
> The Cypselomorphae of Huxley included Swifts, Humming-birds, and the 
Nightjar group. 
