Bird’s nest soup is indeed made from the nests of the swiftlet bird. While it may initially sound gross to make a soup from a bird’s nest, you aren’t actually using twigs and mud. The swiftlet bird makes its nest from its silvia, which hardens to form the nest. You probably want the twigs now. 

The hardened nest is steamed and soaked in a mixture of water and rock sugar overnight. In the morning, remove any feathers from the mixture, and chop up the nest. Place the pieces in boiling water with additional rock sugar, and simmer for two hours. The result is a sweet, syrupy soup with floral and a slight mineral taste. Chinese tradition says bird’s nest soup is beneficial for many ailments and is known as the ‘caviar of the east.’