Oilbird
Encyclopedia : O : OI : OIL : Oilbird
The Oilbird (Steatornis caripensis) is a slim, long-winged bird related to the nightjars. It is sufficiently distinctive to be placed in a family and suborder (Steatornithes) of its own. It is found in the northern areas of South America from northwestern Colombia and the island of Trinidad to eastern Venezuela, Peru and Bolivia in forests and woodland with caves. It is a seasonal migrant, moving from its breeding caves in search of fruit trees. It has occurred as a rare vagrant to Costa Rica, Panama and Aruba.
This nocturnal species, uniquely, is a specialist feeder on the fruit of the Oil Palm and tropical laurels. All the other nightjars and their relatives are insectivores.
The Oilbird's feet are small and almost useless, other than for clinging to vertical surfaces. However, it is capable of hovering and twisting flight, which enables it to navigate through restricted areas of its caves.
This is a large bird at 41-48 cm. with a hooked bill and stiff tail feathers. it is mainly reddish-brown with white spots on the nape and wings.
During the day these gregarious birds rest on cave ledges. The nest is a heap of droppings, on which 2-4 white eggs are laid. The squabs become very fat before fledging, weighing up to half again as much as the adult birds do. They used to be harvested and rendered for oil, whence the name "oilbird".
(a man is standing in the cave mouth)
Although the Oilbird forages by sight, it is one of only a few birds, and the only nocturnal one, known to navigate by echolocation in sufficiently poor light conditions, using a sharp click for this purpose. It also produces a variety of harsh screams while in its caves. Entering a cave with a light especially provokes these raucous calls; they also may be heard as the birds prepare to emerge from a cave at dusk.
The oilbird is called a "guácharo" or "tayo" in Spanish, both terms being of indigenous origin. The "Cueva del Guácharo" (Oilbird Cave), in the mountainous Caripe district of northern Monagas, Venezuela, is where Alexander von Humboldt first studied the species. The caripensis of the binomial name means "of Caripe", and Steatornis means "fat bird", in reference to the fatness of the squabs.
The "Cueva del Guácharo" was Venezuela's first national monument, and is the centerpiece of a national park; according to some estimates there may be 15,000 or more birds living there. Colombia also has a national park named after its "Cueva de los Guácharos", near the southern border with Ecuador. Oilbirds have been reported in various other places along the Andean mountain chain and in Brazil: they are known to dwell as far south as the Carrasco National Park in Bolivia. Dunstan Cave, at the Asa Wright Nature Centre in Trinidad, is home to about 200 nesting pairs of oilbirds.
References
- BirdLife International (2004). [Steatornis caripensis]. 2006 IUCN Red List of Threatened Species. IUCN 2006. Retrieved on 11 May 2006. Database entry includes justification for why this species is of least concern
- ffrench, Birds of Trinidad and Tobago ISBN 0-7136-6759-1
- Hilty, Birds of Venezuela, ISBN 0-7136-6418-5
- Stiles and Skutch, A guide to the birds of Costa Rica ISBN 0-0814-9600-4
External links
- [Cueva del Guácharo (ShowCaves)]
- [Colombia's "Cueva de los Guácharos" National Park]
- [Oilbird videos] on the Internet Bird Collection
From Wikipedia, the Free Encyclopedia. Original article here. Support Wikipedia by contributing or donating.
All text is available under the terms of the GNU Free Documentation License See Wikipedia Copyrights for details.