A green tote bag lay next to it. Within the bag, an Oilbird feather betrayed the use of the bag. Penetrating deeper into the cave, we found that the numbers of this avian colony have indeed been reduced. The few birds that flew off their nests and clucked over our heads in the darkness no longer boasted of a thriving lot of birds. The numbers have been so depleted that some nests now lie empty, there not being high demand for space any longer.
Oilbirds are a gregarious lot, nesting on ledges along the darkened walls of caves.
They are easily distinguished first by their screams and snarls when there is an intruder, then by the line of white spots on their wings, very outstanding on their rich brown feathers in the darkness. Since they nest in pairs, both the male and female presiding over the nest, it is easy for an intruder to benefit from a catch of two at a time, the nest being very shallow and 'on the edge' of the ledge, secured by their own regurgitated paste. During their forages at night, they are harder to catch, as they remain high in the branches of the canopy, feeding on manac and other palm seeds for sustenance. In the largest and most heavily-populated cave in Aripo, the numbers of the colony here have increased so dramatically that there is overcrowding in the main habitation of the cave. In another remotely located cave to the east, north of Cumaca, among the crags and crevices of the 'badlands' of the mountains, the situation is the same.