About Swiftlets

There are many species of swiftlet family around the world but not all species of swiftlet can produce edible nest. Only 5 species from the family of Apodidae known scientifically as Coolocalia Fuciphaga (White-nest swiftlet), Collocalia Maxima (Black-nest swiftlet) are the most heavily harvested nests and the swiftles are found primarily in the coastal and limestone caves of South East Asia. The limestone caves are dark with a constant high humidity. The coastal caves have a higher humidity but are generally brighter and noisier due to the waves. Ecological factors and types of foods consumed will influence the quality, color, texture and size of the birds' nests.

Swiftlets are very unique birds. They have short bills, wide mouths, long, crescent-shaped wings and short and tiny legs not for perching or walking but their legs are just what is needed to cling to stony surfaces like cave walls where they build their nests. Based on these specifications, they have a very strong ability and endurance to fly. In fact, they are the fastest flier known, capable of a 40 hours non-stop flight. The average longevity of the bird is varies from 10 to 20 years. Their nests are made of “nest cement” secreted from glands underneath the bird’s tongue….are what make the Chinese (especially) view the swiftlets with difference.

White nest swiftlets find their way around in total darkness by echolocating (using sound & echoes to navigate). It is audile to the human ear as a series of rattling clicks. The only other bird that uses echolocation is the oil bird of South Africa. In the open, the swiftlets superb eyesight allows them to feed on small insects which they catch in midair. When foraging for their young, anything from 50 – 1,100 insects including beetles, ants, wasps, bees and mayflies have been found compressed into a food bolus which is regurgitated at the nest. Natural predators of swiftlets in caves include pythons, bat hawks, giant crickets and ectoparasites.

During breeding season, the male swiftlet construct their nest with glutinous strands of starched like saliva produced by a pair of large, salivary glands under their tongue over a period of 35 days. The nest looks like a cupped hand or a half cut bowl about 3 – 5 inches in diameter and stuck to the cave wall.

The building process includes chewing and retching during which saliva is extruded onto the nest. It takes 30 days to build a nest and another 7 – 10 days before the first egg is laid. Eggs are usually laid in pairs and then incubated for 3 – 4 weeks. On average the swiftlets have two broods a year. Hatchings remain in the nest for about 2 months.

Harvesting of edible bird's nest/swallow nest

The first harvest begins in March which corresponds with the mating season. The female birds will construct the nests for laying eggs. They build the nests during the night and go looking for food during the day. It will take 30-35 days to finish a nest. Thus, the excellent opportunity for the collectors to harvest the nests is by day when the mother birds are not in the cave. The harvest must be done before they lay eggs. Otherwise, the eggs will be damaged. And as a result, the female birds will no longer lay eggs for the rest of the year. However, if the collectors collect the nests too soon, the quality of the nests will not meet standard because they have not been fully developed.

When they see the nests disappeared, the mother-to-be birds, out of their instinct to maintain their species, will build a second nest. That is why after the first harvest, the collector will wait one month for the birds to construct a new nest. After the second nests are harvested, another three months will be allowed to pass before the third nests are ready for harvesting for the last time of the year in August.

The third nests are the nest where the baby birds live and grow. The reason to wait for three months is to allow time for the baby birds to hatch out of the eggs and to grow up strong enough to fly and forage. The mother birds will spend one month to incubate. After the third nests were harvested, the cave will be isolated until the next year.

Over the past 20 years, the demand and price of these nests have increased. Due to the demand, some bird-nest merchants in Southeast Asia (Indonesia, Vietnam, Thailand and Malaysia etc) have started to raise and breed the swiftlets in house-like structures form. The swiftlet farmers simulate the conditions of a cave in their building or house-like structure form by installing humidifiers and boarding up vents and windows, leaving only small holes for the swiftlets to enter and exit. In comparison between cave nest and house nest, the house nest texture is smoother and cleaner as the cave nest contains more dirt and feather.

Indonesia supplies well over half of the 200-tonne global demand every year follow by Thailand and Malaysia.

The nests are traditionally harvested from high up on cave walls and there is some risk to the collectors who stand on bamboo scaffolding that is sometimes hundreds of feet tall.

Harvesting of birds' nests would start in the early morning when the birds have left their caves for food. The collection would last until about sunset. The long bamboo scaffoldings used for climbing are called 'walking bamboo' because these poles can be moved from place to place. The piles of bamboo stacked on the ground are left over by other hunters after repairing their scaffoldings. Sometimes, like mountain climbers, the harvesters hammer metal poles into rocks and boulders to attach themselves to the cave walls.

During the peak season between February and May each year, harvesters clamber up trellises of bamboo and vines at sunrise, only descending at sundown. To keep their hands firmly on the trellises or bamboo scaffoldings, some times as high as 200-300 feet from the cave floor, they balance torchlight between their teeth to look for what they call “White Gold”. One harvester can collect as many as 50 or 60 nests a day.

Harvesters have to strictly hold on to the conservation principles which aim to sustainably make the most of bird's nests. That is to utilize them for the longest possible period of time and produce the least waste. Harvesting the nests especially for the third time means that although the nests are of poor quality, they had better be collected than be allowed to decay since the baby birds have already left the nests.