Steatornithidae – Oilbird

The main food item in the chick's diet is palm fruit; due to this oily diet, they were once caught and boiled as lamp oil

The Steatornithidae family is unique among avian families for its sole member, the oilbird (Steatornis caripensis), a nocturnal, fruit-eating bird native to northern South America. Known locally as “guácharo,” oilbirds are the only known birds to utilize echolocation, a trait more commonly associated with bats, to navigate through their dark cave habitats.

Oilbirds are medium to large birds with wingspan exceeding half a meter (about two feet). Their plumage is a rich chestnut brown mottled with white spots, which provides excellent camouflage in the dimly lit environments they prefer. The sensory adaptations of oilbirds are truly remarkable; they have extremely large eyes, which are among the most light-sensitive of any bird, allowing them to see in near-total darkness. Their sense of smell is also highly developed and is essential for locating the ripe fruits that make up their diet.

Unlike other nocturnal birds that feed on insects, oilbirds are frugivores with a particular preference for the fruit of oil palms, hence their name. Their diet has a high-fat content, which was historically exploited by humans who would harvest the birds for their fat, using it as oil for lamps.

Oilbirds breed and roost in colonies within the sheltered environment of caves, which protects them from the elements and predators. The use of echolocation enables them to expertly navigate these pitch-black environments. They produce a series of clicking sounds that bounce off the walls of caves, allowing them to “see” their surroundings through sound.

Oilbirds are also known for their nocturnal foraging trips, where they will fly out from their caves at night in search of food. They have been known to travel considerable distances in their quest for fruit, sometimes several kilometers in a single night.

Despite their adaptations to cave life, oilbirds are fully capable of flying in the open air and exhibit strong and direct flight. However, they are rarely seen by day and prefer to leave the safety of their caves only under the cover of darkness.