The Bird's Nest is a kind of bird called Jin Siyan. It is made of moss, seaweed and soft plants by mixing their feathers and saliva.

The nests built by the old people in Jin Siyan are completely condensed by a large amount of mucus secreted by their throats, and the texture is pure. This kind of bird's nest has the best quality, which is the top grade of bird's nest, that is, "Bai Yan".

Due to lack of nesting experience, the nest made by young Jin Siyan is rough and contains many impurities and feathers. The bird's nest materials collected at this time are called "Mao Yan".

Another kind of bird's nest is wetted by the red liquid oozing from the attached red rock wall, and the part of bird's nest near the rock wall gradually turns red, also called "blood swallow" or "red swallow", which contains some minerals, has good nutrition and low yield, and is regarded as a treasure in bird's nest.