The makers of bird's nest are of course swallows, but this kind of swallows is not the swallows that we often nest under the eaves. Swallows under the eaves belong to Swallow Family. Their nests are made of grass or mud and saliva, which makes them inedible and has no nutritional value. Edible bird's nest is made of another kind of swallow, belonging to Chrysopteridae, and is called "Jin Siyan". Specifically, it refers to a nest made of saliva secreted by some Jin Siyan species of Chrysopteridae and several Jin Siyan species of Swiftlet, and then mixed with other substances (such as feathers), rather than a nest made of passerine birds (such as Ru Yan). Among them, Jin Siyan saliva has the highest protein purity and nutritional value. Produced in the southern coastal areas of China, Viet Nam, Thailand, Malaysia, * * * * and the Philippines. Bird's nest is divided into "domestic swallow" and "cave swallow" according to nesting sites. The nest of "Domestic Swallow" is usually built on a man-made house to facilitate the collection of bird's nest, while Dongyan's nest is built in a cave with steep terrain, which is quite dangerous to collect. There is a "blood swallow" in the bird's nest. Because Jin Siyan's food contains seaweed and other things, its saliva is named HongLing, not because people misunderstand that it didn't finish the bird's nest and couldn't hold back laying eggs and vomiting blood. After picking bird's nest, it has to undergo complicated processing such as steaming, soaking, removing impurities, picking hair and drying. Can be made into finished bird's nest, including Yan Yan, Yan tiao, Yan Bing and Yan Si. Swallow cup is a kind of large and high-quality bird's nest, which is made by removing impurities and keeping its original shape, and the price is particularly expensive.