In the afternoon, we left the Escalera and drove up to Waqanki. Along the way, we stopped at Quisquarrumi bridge, a well-known site for Oilbirds. Oilbirds are a monotypic family in the nightjar order; like other nightjars, they are nocturnal, but they are peculiar in several ways. They are the only nocturnal fruit-eating birds, foraging on fruits of the oil palm and tropical laurels. They may fly up to 120 km nightly in search of fruits. They are the only birds that navigate by echolocation, like bats, but at a lower frequency that is audible to humans. The chicks get very fat on their diet of oil-rich fruits, out-weighing the adults. It is said that in the past chicks were captured and boiled down in order to make oil, hence the name Oilbird. They spend their days resting on ledges in caves, where they also nest. At Quisquarrumi, they rest on ledges in a cave-like rock crevice. There is a highway bridge over the crevice, and one can easily look down on the birds from the bridge, although the dim light makes photography difficult.