Dongyan: It is the nest made by swallows in wild caves and coastal cliffs. The living environment of Siyan was destroyed due to early disorderly indiscriminate mining and excavation. Now, only bamboo ladders used for picking are left in some caves in Thailand, and swallows have long been few. With the scarcity of Dongyan production and the growing voice of environmental protection, they are gradually replaced by house swallows.
House Swallow: From Dongyan to House Swallow, the nesting environment in Jin Siyan is changing, but the living habits have not changed. Jin Siyan is still wild. It goes out for food in the morning and comes back in the evening. Due to the artificial protection, Jin Siyan has multiplied more and more, and the built bird's nest is picked in time, so the nutrients are not lost.
And these two kinds of bird's nest will be divided into color, shape and morphology.
By color: Blood Swallow (must be Cave Swallow), Huang Yan and Bai Yan.
According to the specifications, it is divided into: Yan Zhan, Yan tiao, Yan Si, Yan Bing, Yan Broken and Yan Jiao.
According to the production form: grass swallow and hairy swallow
Among all kinds of official swallows, Bai Yan lamp is the most tender and less fire-resistant. Especially the house swallow. This is because the picking time of bird's nest is the shortest in the Yanwu (once every three months on average). In addition, the structures of house swallows and cave swallows are different due to different nesting species in Jin Siyan. The silk strips of the white-house swallow are thin and smooth, while the silk strips of the white-hole swallow are slightly rough. Therefore, it indirectly affects the stewing time and temperature of bird's nest. The Bai Yan lamp in the cave has a solid texture and a large expansion force. After the top-grade hole Bai Yan is stewed, it is not only fragrant, but also fragrant, smooth and refreshing.
White bird's nest is actually a color of bird's nest, which is whiter than Huang Yan and Xue Yan, but it is not all white, and it will be a little yellow inside.