In the last two years, Nha Trang Bay in Khanh Hoa Province has been making waves for something other than its beaches, diving and seafood.
Enamored of its health benefits and curious about its origins, tourists have been flocking to the islands where Bird's Nest is found nests that are built with the saliva of the swiftlet birds.
The Sanest Tourist Company has been operating tours to these islands since 2009. Visitors are taken on a two-hour boat trip to Hon Noi Island and led into dark caves to watch the swiflets with the help of flashlights.
The swallow-like bird in Nha Trang has been identified as the German's Swiftlet (Collocalia germani or Aerodramus germani) - a species of swifts found in China, Indonesia, Laos, Malaysia, Myanmar, the Philippines, Singapore, Thailand and Vietnam. Its natural habitats are subtropical or tropical moist lowland forests and mountainous regions, according to the International Union for Conservation of Nature.
It is estimated that the Nha Trang Bay has more than 500,000 cave swiftlets that have made its sheer cliffs their home.
The swiftlets breed in colonies in caves, in clefts in cliffs on Nha Trang's islands. Their bracket-shaped nests are white and translucent and made of layers of hardened saliva.
The solidified saliva is now gathered and used to make bird's nest soup and other beverages that people say are not only tasty but also have several health benefits.
According to bird-nest workers, swiftlets live in pairs and do not perch anywhere but in their own nests.
Day after day, the male and female swiftlets drop their saliva in sticky transparent strands on the rocks. The interwoven strands slowly take the shape of a solid nest, looking like a shallow cup or an oyster shell.
HOW TO GET THERE
You can book a tour to the Bird's Nest islands at:
Sanest Tourist Center
89 Thong Nhat Street, Nha Trang
Tel: (058) 3 818 191 - 3 818 189
If their nests are taken away ("˜harvested'), the birds make a new one.
The swiftlet's nesting season usually lasts from December until March every year. Two to three months after making the nest, the female birds lay eggs. The chicks begin flying a couple of months after hatching.
Old solid bamboos are soaked in seawater and used to build a scaffolding for workers to reach the caves.
Some visitors may feel uncomfortable looking into a deep dimly-lit cave smelling of bird poop and salty seawater, but the workers do not notice anything untoward, apparently.
Wearing just shorts and safety belts, they bring with them a pack to collect the bird's nest, a water bottle "˜spray,' a device to pry the bird's nest off the cliff and a flashlight.
They climb on the bamboo scaffolding to approach the cliff, doing their job very carefully as the nests must be taken intact.
There are some caves with entrances too low and narrow to get into by boat, so the workers tie themselves with ropes and throw themselves off the cliffs to enter the caves below.
Collecting bird's nest has become a hereditary job. Once a worker retires, his brothers or children are trained to continue working in the caves.
According to locals, bird's nest harvesting dates back to more than half a millennium ago when Le Van Dat, a commander of the Tran Dynasty (1255-1400), found the bird-nest caves in Hon Tre Island. The industry has developed ever since.
However, it is not easy work. It takes courage, good health and skills to climb the scaffolding and swing off the cliff with strong waves thrashing on the rock underneath.
Concentration and calmness is key.
Locals say that because the work is hard, only people from the same family have enough patience and dedication to teach the skills to one another. The apprentice will be led by his father or brother to the bird's nest caves, and learn by watching they do.
Those assigned to guard the nests also have a tough job on their hands, especially when fishermen in fishing boats staying on the islands overnight try to get their hands on the lucrative nests.
The security workers must live far from home for months on the separate islands where freshwater, vegetables and food have to be brought in from the mainland.
In Vietnam, a kilogram of bird's nest can fetch as much as VND60 million (US$2,871). That makes exploiting the bird's nest a lucrative business, and it is called "white gold on the sea."
So far 27 bird's nest islands with 102 caves have been found in Nha Trang, and more than 3,000 kilograms of the precious commodity is harvested a year.
The price of an exported kilogram of bird's nest harvested from the cave is US$2,469, and it is reported that companies in the business earned VND380 billion ($18.2 million) last year.
The wild (or cave) bird's nest is obviously more expensive than those that are bred.
Dubbed "Caviar of the East," bird's nest soup is a delicacy in Chinese cuisine and several Asian countries including Vietnam. A small bowl of bird's nest soup served on the tour in Nha Trang costs VND220,000 ($10.52).
The authentic bird's nest soup may taste quite rubbery to Westerners the first time, but Vietnamese cooks make it much more delicious with other ingredients like chicken, lotus seeds (to make sweet soup), and eggs.
The soup has a sweet, gelatinous, almost cartilage-like taste.
The bird's nest is believed to have wide-ranging benefits. It aids digestion, raises libido, improves your voice, restores young and beauty, and strengthens the immune system. It is said that it also has high levels of calcium, iron, potassium, and magnesium.
In Vietnam, wild bird's nests can also be found in coastal provinces in the central region, including Quang Nam, Phu Yen and Binh Dinh.