Bird's nests are nests of swallows, but they are not nests of common house swallows, they are nests of swiftlets and other swallows of the same genus in the family of Apodidae, and only their saliva can build nests, and they are bird's nests. Swiftlets have developed sublingual gland in their throat, which secretes sticky saliva, which is the raw material of bird's nest. However, the bird's nest cannot be consumed directly after it is harvested, it needs to be processed and handled.

Bird's nest is a nest of swallows, but it is not a nest of common house swallows, it is a nest of swiftlets and other swallows of the same genus in the family of Apodidae, and it is only their saliva that can build a nest, and it is a bird's nest. The swiftlet's throat has a well-developed sublingual gland, which secretes sticky saliva, which is the raw material of bird's nest. However, the bird's nest cannot be eaten directly after it is picked, it needs to be processed and handled.