SALIVA STRUCTURES
While some birds scavenge for perfectly shaped sticks to build their nests with, the edible-nest swiftlet makes its own biological building material. During the nest-making process, the birds’ salivary glands enlarge. Edible-nest swiftlets are born in a nest made of 100 per cent saliva.
The saliva is released onto a flat, vertical surface like a rock or wall, and a basket-like nest is designed by the bird. The saliva hardens as it makes contact with the air to stick to the wall and existing nest. When complete, the nests are about six centimetres long and 1.5 centimetres deep – capable of holding two eggs.
The species is named the ‘edible-nest swiftlet’ because this bird’s spit creation is a delicacy in Chinese cuisine. Most commonly these nests are added into soups. The nests have been a traditional dish for at least four centuries and are believed to have nutritional value. One particular suspected health benefit of the soup is the assistance of skin and tissue repair.