Three times a year, swiftlets build nests out of their sticky saliva on cave walls and cliff sides, where they raise their young. It's the high cost of these saliva nests that makes bird's nest ...

Three times a year, swiftlets build nests out of their sticky saliva on cave walls and cliff sides, where they raise their young. It's the high cost of these saliva nests that makes bird's nest ...

Edible bird’s nest is made by a species of cave-dwelling swiftlets. Weaved from their saliva and harvested in caves and man-made nesting houses, bird’s nests are then painstakingly cleaned ...