1, the bird's nest is the nest of swallows, but this is not the nest of ordinary swallows, but the nest of Jin Siyan. It is a nest made of saliva secreted by several Jin Siyan species of Swift and Swift, and then mixed with other substances.

2. Bird's Nest is a kind of bird called "Jin Siyan", which uses moss, seaweed and soft plants to mix their feathers and saliva to cement the bird's nest as a hiding place. People take this kind of bird's nest down, and after refining and selecting it, it becomes a valuable bird's nest.

3, "Jin Siyan" nests three times a year, and the first nest is thick and white. Because Jin Siyan has a long winter and has a long time to recuperate, it has stored enough nutrients in its body, and the quality of saliva is excellent, so the nest built is better and thicker, and it is shaped like a lamp, so it is named Yanzhan, which is the best in bird's nest.

4. There is a kind of bird's nest called "Blood Swallow", which is built by a kind of "Jin Siyan with Brown Tail". This kind of swallow may drink different water quality, or its saliva may be red due to factors such as minerals, so it builds a "Blood Swallow" nest. Another is called Bai Yan, which is mostly produced in Indonesia, and another is called Maoyan, which is mostly produced in Brunei and Borneo. This kind of Maoyan is thin, dark and full of feathers and impurities. It is mainly built by a kind of "Jin Siyan with gray waist", and others with too many impurities and feathers are collectively called Maoyan.