Gomantong Hill is the largest limestone outcrop in the Lower Kinabatangan area, and contains at least nine caves. For centuries, the Gomantong Caves have been renowned for the valuable edible birds' nests made by two of the four species of swiftlets that roost in the caves. During the harvesting months, visitors may be able to witness the birds' nest collectors in action. This is an age-old tradition and the trade history of bird nest spans several hundreds of years.
The birds' nests harvesters are individuals who have nerves of steel and skills honed through years of experience. Dangling precariously from the narrow network of ladders is not a task for the faint hearted! It is not surprising that there are only a few experienced individuals who are very much in demand by people and communities that hold the Governments harvesting licenses. Edible birds' nests are protected under the Birds Nest Ordinance and the Forest Enactment. Heavy fines and penalties are imposed on unlicensed collectors.
Birds' nest harvesters usually stay in huts close to the entrances of the caves. Their responsibilities are two-fold - they must harvest the nests according to a biologically sustainable schedule (imposed by the Wildlife Department), and they must also protect the nests from being stolen. The failure to adequately carry out either of these roles could have devastating effects on the swiftlet population and subsequent harvests.
Swiftlets have a slow breeding cycle, and usually lay not more that two eggs each season. Generally, two collections are made. The first takes place early in the breeding season before the swiftlets lay their eggs. The birds then make another nest in which they finally lay their eggs. After the young have fledged, the second collection is made. Care must be taken to assure that the nests are collected only after the young swiftlets have abandoned these nests.
Breeding seasons are particular to different species and the different caves in which the birds roost. At Gomantong Caves, the two edible swiftlet species have different breeding times. For the black-nest swiftlet, the first collection should take place no later than April or May, otherwise the birds will not have time to build another nest. The second harvest then takes place in September and October. The more valuable white-nest swiftlet nests are initially collected in February, and again in June and July. The breeding patterns of the birds are not rigid and must be closely monitored to accommodate any observable changes in their reproductive behaviour.
Tools of the trade
The birds' nest harvesters who are called tukang pemungut still employ time-tested techniques that have been used for hundreds of years. The main prop is the gugulug, a ladder made from coils of rattan rotan saga (Calamus caesius) and hardened belian (Eusideroxylon zwageri or Borneon Ironwood) which may be up to 150 metres in length.
The pietau, is another ladder which usually consist of a rigid bamboo pole about 25 metres long. Rungs are fastened across the bamboo as steps, and additional rattan cords are tied around it to offer some security to the climber. Harvesters use a sesungkit to remove the nests, which are just out of reach. It is a thin hand-held stick of bamboo or light hardwood, which has four sharp steel or bamboo points to dislodge the nests from the cave surface.
The harvester must assess the best combination of these props to be used, based on experience and the location of the nests. When collected, the nests are placed in the ambong, a woven basket that is then lowered to assistants who empty the nests into a large sack.
Besides observing the exciting display of skill and courage by the birds' nest harvesters, another activity for keen naturalists would be to watch the spectacular display of over 2 million or so resident bats as they spiral out for their evening feed. This usually occurs between 5.15 - 6.15pm, but rain sometimes delays or "cancels" this show-time. At the same time as the bats leave, the swiftlets are usually beginning to make their way back to the caves after a day's foraging. The changing of 'shifts' between the bats and birds makes quite a fascinating scene! Look out for the Bat Hawks that are not offer far from the scene, as they prey specifically on the bats as they leave their roost.
It is possible to drive all the way to the Information Centre at the foot of the Gomantong hill. You can also take any of the Sandakan-Sukau buses that will drop you off at the junction to the caves. But be warned, it is about 6 km (3.72 miles) to the caves, so you might want to charter the whole bus for convenience or pay him a little extra to get dropped off at the information centre. If you are already in Sukau, make arrangements with the local bus transport for a day trip to the caves or a stop over on the way back to Sandakan.
Do check with the Wildlife Department in Sandakan for harvesting times. Otherwise, opening times for the Gomantong Information Centre are as follows:
Monday-Thursday (8am-12.45pm & 2-4.15pm);
Friday (8am-11.35am & 2-4.15pm); and
Entry permits are not required except during harvesting times. Please check with the Wildlife Department for the entry permits before you go.
The entrance gate will be kept opened till the last visitor of the day leaves so please inform the Wildlife Department staff on duty if you intend to leave later than the stipulated opening times.