These dried half-cup-like nests, yan wo, made of swiftlets' saliva, are translucent milky white or yellow, a few are deep red. They are top tonics for everyone and sell at high prices. They are usually made into soup.
Bird's nests are big in China. The vast 258,000-square-meter Bird's Nest, or National Stadium, drew the world's applause at the Beijing Olympics last year.
And tiny 6-centimeter-diameter bird's nests are big draws in a traditional Chinese medicine pharmacy.
Prominently displayed, these dried half-cup-like nests (yan wo) made of swiftlets' saliva, are translucent milky white or yellow, a few are deep red. Many are cushioned on satin and preserved under glass.
They are top tonics for everyone and sell at high prices. They are usually made into soup.
The half-moon nests are made of saliva strands that hardens. The swallow-type birds make their nests high on ocean cliffs, against the rock itself. Those who collect the nests climb high ladders or are suspended from cliffs - dangerous work that makes the nests even more expensive.
Depending on size, completeness (actually a matter of aesthetics), color (red is priciest) and packing, the nests can cost about 32-80 yuan (US$4.70-11.70) per gram. Bottled cooked nest weighing 200 grams cost from around 660-1,300 yuan.
One report says one kilogram can cost US$2,000, making bird's nest the "caviar of the East."
Bird's nests have long been a popular tonic especially for women, as they are said to improve the complexion by promoting cell regeneration and reduce signs of aging.
Medically, it is famous for reinforcing energy and relieving respiratory problems.
The saliva contains water-soluble protein, carbohydrates and micro-elements such as calcium, phosphorous, iron, sodium and potassium. It contains antioxidants and helps boost the immune system.
In terms of yin and yang energy, it is neutral.
Clearly this is not just any swift or sparrow's nest.
Swiftlets fly from Siberia to the tropics and sub-tropics for mating and nest-building. They are found in Vietnam, Thailand, Indonesia, Philippines and the southern coast of China. Indonesia exports most of the world's bird's nests.
It takes around 20 days to build a nest with saliva; it is thicker at the bottom and the wall is thin like a shell. It is usually 6-7 centimeters in diameter and weighs 10-15 grams.
The first nest that a swiftlet builds before egg-laying is of the top quality, as it is mostly pure saliva. These nests are called guan yan (official nests), and were given in tribute to emperors in the past.
When the nest is harvested, the poor swift must rebuild and as time is limited it uses other fibers as well as saliva. The second nest, thus, is less nutritious. These nests are called mao yan (rough nests).
Most nests are translucent white or yellows (equally nutritious, color depending on bird's diet), but some are dark red and are called xue yan (bloody nest). The red comes from marine elements and iron in seaweed eaten by the birds. They are especially nutritious, quite rare and, of course, much more expensive.
Since harvesting nests on cliffs is life-threatening to the collectors and can damage the environment, tower-like structures are built for the birds to make their nests. They can fly in and out and harvesting is easy. They provide good spots for nest building and the birds lose less energy and nutrition flying about to find a nesting spot.
After they are harvested, the nests are cleaned and processed. They will be made into yan zhan (complete nest), yan tiao (nest stripes), yan bing (nest cake), yan si (nest thread), and yan sui (nest chips). Yan zhan made of the whole nest are most valuable.
Bird's nest is a neutral-energy tonic that reinforces energy, nourishes the lungs, benefits the spleen and improves the complexion. It travels through lung, stomach and kidney meridians to take effect.
It is used to treat various coughs, chronic bronchitis, vomiting, stomachache and malnutrition. It helps relieve night sweats and frequent urination due to energy deficiency.
"Bencao Gangmu" ("Compendium of Materia Medica") says bird's nest nourishes yin energy in the lungs, resolves phlegm and relieves coughing.
TCM holds that "the lungs govern skin and hair," and so bird's nest tonic can improve skin quality and reduce signs of aging.
Modern research has found the birds' saliva contains antioxidants and elements that promote cell regeneration. Rich protein and micro-elements can boost immunity.
Bird's nest is recommended for everyone. In addition to benefits already noted, it is said to be a male tonic. It can help pregnant women and nourish the fetus and help the elderly by increasing energy and treating respiratory and digestion problems.
As with all herbal therapy, it must be eaten regularly and it takes three to five months to have an effect. For complexion benefits, the best time to eat bird's nest is before you go to sleep; the "golden" sleep period is from 11pm-2am when cell division takes place around eight times faster than at other hours.
Yan zhan (complete nest) is not necessarily more nutritious than fragments; purity is the most important factor. Fragments that have fallen usually have more impurities, which makes cleaning more difficult and may affect taste.
Bottled bird's nest is widely available and can easily be made into soup.
Hungry mariners discovered bird's nest
It is said that Zheng He, the great Chinese navigator in the Ming Dynasty (1368-1644), was the first Chinese to eat bird's nest.
Zheng's fleet was forced to anchor at a desert island due to a big storm.
Food was scarce and the men were hungry. Zheng discovered the nests on cliffs by chance and ordered his men to collect them and cook them.
Amazingly, the sailors all felt strong and energetic and looked well in a few days. They collected more bird's nests as tribute to the emperor.
How to choose the best nest
Observe: Check whether the nest, either whole or in fragments, is translucent and has an irregular surface created by strands of saliva.
Smell: Real bird's nest is virtually odorless; if it smells fishy or greasy, it's a fake.
Touch: Soak a small piece in water; it should get soft and stretch. If it's brittle or gooey, it's fake.
How to preserve
Nests should be sealed before storage in the fridge. If it is moist, it should be dried in cold air, not in sunshine or in the oven.
Cooking basic soup
Common bird's nest soup
Preparation: Soak whole dried nest in water for an hour until it softens, remove impurities. Filter and soak again in purified water overnight, four to eight hours. Remove impurities but retain nutrient-rich water.
Cook in a small double-boiler. About 30-45 minutes are enough for guan yan (official nest), while xue yan (bloody nest) requires 3-3.5 hours because of mineral composition.
When it's almost done, add rock sugar to sweeten. Simmer for five minutes.
Eat once daily every two days. Take for at least three months.