Bird's nest is a nest made of saliva secreted by swallows mixed with other solid substances. Swallows will first find a comfortable place to nest, usually on a cliff with cool weather and comfortable climate. After they choose a place, a female swallow and a male swallow will nest together, because the swallow's throat has developed salivary glands, which can secrete a lot of saliva, and its saliva can solidify into a solid in the air. Therefore, swallows can build nests by secreting saliva to enhance the stability of their nests. When the bird's nest is built, swallows will breed in it. When the swallow hatches and thrives, the mother swallow will leave the built nest with the swallow. Generally, after the mother swallow leaves with her young, she will never return to her previous bird's nest, so it can be picked.

The value of bird's nest is very expensive, because it has high nutritional value, is rich in protein and a certain amount of amino acids, and plays a great role in human body. Eating more bird's nest has many benefits for the human body: women can eat more bird's nest to stay young, pregnant women can eat more bird's nest to supplement enough protein, which is also good for the baby in the womb, and the baby born will be smarter in the future.

Bird's nest is expensive not only because of its high nutritional value, but also because of its high labor cost. Most bird's nests are located on cliffs, so the labor cost in the picking process is high and the picking process is also very dangerous; Secondly, the number of bird's nest is very small, and there are only a handful of wild bird's nest with good quality. It is not unreasonable that bird's nest is so expensive. There are other impurities in bird's nest besides swallow's saliva. These impurities are very small and difficult to pick, which requires good eyesight in the processing process and high processing cost, so the price of bird's nest is also very high.

Although bird's nest is expensive, its nutritional value is very high, which is worth the money.