ocr: SEEING WITH SOUND The South American oilbird isa nocturnal fruit-eater that nests deep in caves. Like bats, oilbirds use sound to find their way through the darkness. When flyingin a cave, the oilbird produces a series of metallic clicks. It listens for the echoes that bounce back and uses these to keep clear of the cave's walls. This is called echolocation. Each bird can pick our its own clicks from those of the hundreds ofother oilbirds in the cave. SEE ALSO
