OIL BIRD

*Oilbird (_Steatornis caripensis_) – The Nocturnal, Fruit‑Eating Cave Dweller –

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Introduction
The *_Oilbird (_Steatornis caripensis__) is a unique, night‑active bird found in northern South America, famous for its *echolocation*, *fruit‑based diet*, and the *historical use of its chicks for oil*. It is the sole member of the family *Steatornithidae* and one of the few birds that navigate in total darkness using a sophisticated click‑based sonar system.

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Taxonomy & Naming
- *Scientific name:* _Steatornis caripensis_ (Humboldt, 1817)
- *Family:* Steatornithidae (monotypic)
- *Order:* Caprimulgiformes (nightjars, nighthawks) – though it differs in diet and habits.
- *Etymology:*
- _Steatornis_ = “fat bird” (Greek _stear_ = fat, _ornis_ = bird) – refers to the oily chicks.
- _caripensis_ = “of Caripe,” a Venezuelan locality where Alexander von Humboldt first described it.
- *Common names:* Oilbird, *Guácharo* (Spanish, from indigenous “wa’chara” meaning “one who cries”).

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Description
- *Size:* Medium, about the size of a small hawk.
- Length: *40–49 cm (16–19 in)*.
- Wingspan: *91–100 cm (36–39 in)*.
- Weight: *350–485 g (12–17 oz)*.
- *Plumage:*
- *Upperparts:* Dark brown with white‑spotted “scales” on wings and back.
- *Underparts:* Pale buff to rufous, spotted with white.
- *Head:* Large, round, with a strong, hooked beak and a flat, wide face.
- *Eyes:* Relatively small, dark, adapted for low light.
- *Legs & Feet:* Weak, short, with long talons; used mainly for perching on cave walls.
- *Sexes:* Similar in appearance; females slightly duller.

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Habitat & Distribution
- *Range:* Northern South America:
- *Venezuela (Cueva del Guácharo National Park), Colombia, Ecuador, Peru, Bolivia, Brazil (Amazon basin), Guyana, Trinidad.*
- *Habitat:*
- *Caves (roosting & nesting)* – deep, dark limestone or sandstone caverns.
- *Foraging:* Montane and lowland tropical forests, especially where *oil‑rich fruits* (e.g., _Dactylopia, Ocotea, Lauraceae_) are abundant.
- *Elevation:* Sea level to *2,200 m (7,200 ft)*.

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Behaviour & Ecology
Diet
- *Frugivorous (fruit‑eating)* – almost exclusively feeds on *aromatic, oily fruits* (laurel family, palm fruits).
- *Foraging:* Leaves cave at dusk, flies up to *30 km* to feeding sites; returns before dawn.
- *Digestive adaptation:* Very slow gut passage (up to *30 hours*), allowing maximum fat extraction.

Echolocation (Clicking)
- Emits *short, audible clicks (2–4 kHz)* in bursts of 2–6 clicks per second.
- Uses *time‑delay* of returning echoes to navigate through total darkness of caves (similar to bats, but vocal).
- Clicks also serve *social communication* within colonies.

Social Structure & Breeding
- *Colonial:* Hundreds to thousands of pairs nest together on cave ledges.
- *Monogamous pair bonds* (often lifelong).
- *Breeding season:* Varies by region (often aligned with fruit peaks).
- *Nest:* Simple scrape on cave ledge, sometimes lined with regurgitated fruit seeds.
- *Clutch:* 2–4 white, oval eggs.
- *Incubation:* 32–35 days (both parents).
- *Chick:* Hatchlings are *altricial*, covered in down; grow rapidly, becoming very *fat (30 % body fat)*—a source of “oil” for historical use.
- *Fledging:* 110–125 days after hatch.

Vocalisations
- *Clicks for echolocation.*
- *Loud, wailing screeches* and *whistles* for communication in colonies.

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Conservation Status
- *IUCN Red List:* *Least Concern (2023)* – wide distribution, large population (estimated several hundred thousand).
- *Potential threats:*
- *Habitat loss* (deforestation of fruiting trees).
- *Cave disturbance* (tourism, mining).
- *Historic harvesting* of chicks for oil (now illegal in most countries).
- *Protection:*
- Cueva del Guácharo (Venezuela/Colombia) is a UNESCO World Heritage Site.
- National parks and reserves across range.

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Interesting Facts
- *Oil source:* Indigenous peoples and early expl