Edible-nest Swiftlet: Little Bird with an Expensive Nest

On a pitch-dark night in the dank forest of the Andaman Islands, I could only hear soft “ticking” sounds that indicated the arrival of the edible-nest swiftlet (Aerodramus fuciphagus). I was with Dr Shirish Manchi, scientist at the Salim Ali Centre for Ornithology and Natural History (SACON) who was counting the number of edible-nest swiftlets returning to a deep cave on Interview Island.

It was 3rd February 2019 and we started from Mayabundar at 4.30 am reaching Chengappa Bridge over Austen Strait which connects the Middle and North Andaman islands. Austen Creek is the largest creek in the Andamans and it took us 1.5 hours to cover it on a small motorboat. On both sides, were fabulous mangroves, followed immediately by tall, dense forests. We reached Interview Island by 7.20 am and, after some pleasantries with the policemen and forest staff, started walking the 13-km distance to reach the swiftlet protection camp. While I was engrossed in making notes of the endemic birds that I could hear and see, Shirish and his student cautioned me about 9-10 “wild” elephants that occupy this 134-sq-km island. Although we saw dung piles in many places, we didn’t encounter any elephants. Another animal introduced by the British in the Andamans (including on Interview Island) was the chital or spotted deer (Axis axis). We heard a few chital calls and saw dung pellets in many places but did not see the animal.

When colonial timber operations were underway, elephants were brought in to move the lumber. Interview Island is now a wildlife sanctuary, with tree cutting banned four decades ago. The small elephant population roams free and sometimes troubles the unwary staff.

Hot dal, rice, and sabzi greeted us when we reached the field station at 1.30 pm, totally exhausted from the long trek in the hot, humid forest. This was followed by a quick post-lunch nap to revitalise us. In a tropical forested island, with 35-40 degrees C temperatures and 80-90 per cent relative humidity, siesta is a daily routine. So far east, the sun goes down by 5 pm.

Shirish and the forest department had numbered the caves. Shirish told me that white-bellied or glossy swiftlets (Collacalia esculenta) and edible-nest swiftlets roost in the same caves, but glossy swiftlets return before dusk as they cannot echolocate (navigate using reflected sound). We sat in the forest in the fading light, slightly away from mouth-1 of the swiftlet cave. His students and the other swiftlet protectors went to collect data from mouth-2. Shirish counted the number of glossy swiftlets entering the cave — the task made more difficult by some individuals flying out and returning. This counting was a prelude. Soon it was time for the grand finale — the purpose for which I had come to the Andaman Islands again. In total darkness, when I could not see my own hand, the first edible-nest swiftlet arrived. Even the call of the endemic Hume’s hawk-owl (Ninox obscura) could not divert our attention as we started counting the “tick-tick” sounds that indicate the arrival of an edible-nest swiftlet. First, they came in a trickle, but after about 20 minutes, the arrival frequency increased, and within 30-40 minutes, almost 70 per cent of the population of this cave had entered the roost site. Sometimes 3-4 came simultaneously, so only an experienced person like Shirish could count them. Till 7.50 pm, we counted about 175 edible-nest swiftlets entering the cave. After an hour, when the “tick-tick” stopped, we walked back to camp, about 50 m away, with Shirish’s head-lamp guiding us.

About 50 years ago, in my MSc zoology book, I read that the nest of a bird is eaten, but my real introduction to the edible-nest swiftlet was given by my former student, the late Dr Ravi Sankaran, who started his BNHS stint with me in 1985. In 1994, Ravi joined the newly established SACON and soon started working on birds of the Andaman and Nicobar Islands. After his remarkable work on the Nicobar megapode, he shifted his attention to the edible-nest swiftlet. He soon found that it is impossible to protect its nests from poachers by the conventional carrot-and-stick policy. He came up with a revolutionary idea: make nest-harvesting an economic activity so villagers and locals will have a stake in protecting it.

Many swiftlet species produce edible nests used in east Asia to make soup. For example, the Indian swiftlet (Aerodromus unicolor) of the Western Ghats and Sri Lanka, produce nests but add small twigs and feathers to them, so their nests are not so valued. The edible-nest swiftlet produces a small cup-shaped nest from pure saliva. Such nests in Indonesia, Malaysia, China, and Hong Kong are in high demand, selling at USD400 a kilo.

In many countries, they are extensively farmed, breeding colonies are protected, and nests are harvested after the breeding is over. Special houses are built and modified to encourage swiftlets to nest in artificial nesting colonies in Indonesia, Malaysia, Thailand, Vietnam and more recently in Cambodia. Research has shown that we can create conducive conditions that simulate natural limestone caves. Many large nesting colonies have been established in houses where villagers protect the bird and harvest nests at the beginning of the season, so the birds make another nest in which they raise chicks. Once the chicks have flown, these used nests are also harvested. Like many colonial nesting birds, edible-nest swiftlets come back to nest in the same area again and again, making a new nest every breeding season.

The Andaman edible-nest swiftlet is endemic to the Andaman and Nicobar Islands. Ravi conducted extensive surveys all over the Andaman and Nicobar Islands and concluded that conventional methods cannot protect nest caves from poachers. Poachers were more knowledgeable and innovative than the forest guards, and they were more determined too. In remote caves, poachers have to be successful only once in order to harvest all the nests, while the guards have to be vigilant all the time. The odds were in favour of nest poachers. Locals had no interest in protecting the bird as they had no benefit from nest harvesting. So, Ravi suggested that the government allow sustainable harvesting of nests. As the swiftlets were brought into Schedule I of the Indian Wildlife Protection Act in 2002, no part, including used nests could be sold. It took us ten years, and many meetings to “temporarily” delist it from Schedule I so that a new type of conservation paradigm could be applied for this species. According to this policy, implemented in 2012, villagers were allowed to sustainably harvest nests.

Unfortunately, Ravi Sankaran died in 2009 before he could see the fruits of his efforts. His student Shirish Manchi left without a mentor, took up studying these birds and fortunately continues to do so. He was conducting pioneering studies on the ecology, breeding success and behaviour of this species in the Chalis-Ek caves. When I visited him the Andamans in February 2012, I was amazed to see Shirish’s student, the young Akshaya Mane, living in a remote jungle hut with 10-12 forest guards and local nest protectors. She was doing her PhD on edible-nest swiftlet roosting behaviour. A visit from her mentor’s mentor’s mentor excited her. Despite my claustrophobia and fear of narrow dark spaces, Akshaya managed to convince me to enter the narrow cave and see the nests. Such was the power of her persuasion that I agreed.

We all know that nocturnal bats echolocate to find prey/food and each other. Swiftlets, along with oilbirds (Steatornis caripensis) of South America are the only birds known to possess this ability to echolocate. They forage during the day and catch aerial insects by sight like other swiftlets, but to return to the caves for roosting/breeding, they use their echolocation abilities. Edible-nest swiftlets emerge from their roosting caves at dawn and return for roosting at dusk.

Many countries have made sustainable use of nests of edible-nest swiftlets and turned it into a cottage industry. As a result, there are millions of free-flying swiftlets. In India, however, the debate is still on whether to allow sustainable harvesting or not. Villagers and locals have lost interest in protecting the caves/nests as they see no returns, the dedicated forest guards look for direction from their bosses, research work suffers from a lack of funds. The best way to protect the nests from poachers is to commercialise the sale so villagers have an economic benefit and continue supporting the swiftlet conservation plan.