Which fruits do oilbirds eat?

The oilbird is unique among the order Caprimulgiformes as an exclusively frugivorous bird. While other members of this order are primarily insectivorous, oilbirds feed on the fruits of various trees, specifically those belonging to the palm, laurel, and bursera families.12

These fruits are characterized by their large, hard seeds and a firm, fleshy pericarp that is exceptionally rich in protein and oily fats. When feeding, the oilbird hovers to pluck individual fruits from trees, swallowing them whole before later regurgitating the seeds. While the bird uses its sense of smell to locate certain aromatic fruit-bearing trees, it relies on sight to find non-aromatic palm fruits and to perform the actual collection of the food.12