TAN MARDUKA¹

During this study, the birds and mammals coming to a fruiting fig tree, Ficus benjamina, over a period of 24 hours were monitored. This was a very short study, and the results may have been affected by nearby human disturbance and rain.

During my survey, hundreds of small birds were recorded feeding at the Ficus benjamina tree. Few big birds and big mammals fed on fruits during the study, perhaps because they are too small (7 to 8 mm diameter), or maybe due to previous hunting. The big animals seen were Black Hornbill, Long-Tailed Macaque, Banded Langur and Giant Squirrel. The sighting of Banded Langur near the park’s northern boundary is significant because it confirms recent reports that they have appeared in the area.

Fig trees can be an invaluable tourism resource for Niah National Park, where visitors can do bird watching when they are fruiting. Ficus benjamina is a keystone species in the forest and I would suggest more patrolling and enforcement work be done when they are fruiting. The importance of fig trees should be stressed in the Education and Interpretation Unit’s rural programme.

Niah National Park is located in the northern region of Sarawak. It was gazetted in 1974 with an area of about 3,140 hectares. It is about 3.8 km from the small town of Niah. The park is covered with limestone vegetation, mixed dipterocarp forest, peat swamp and regenerated forest. About 190 bird species and 64 mammal species have been recorded in the Park (Good, 1991).

Figs are plants of the Ficus genus, which may be trees, shrubs, epiphytes or climbers. About 67 Ficus species are recorded in Sarawak (P. Chai, pers. comm.). Figs are found in most habitats especially in the peat swamp forest and limestone cliffs of Niah Mountain.

Ficus benjamina is a strangling fig. The fruits are small (~7 to 8 mm in diameter) compared with most fig species. The seed is deposited on a tree branch in the droppings of arboreal animals. Here it geminates and develops an extensive crown of long branches, which compete for light with the host tree. The host may finally die from inadequate light.

The objective of this research is to record the bird and mammal species visiting a fruiting Ficus benjamina in Niah National Park over a period of 14 hours.

The study site is near the northern boundary of the Park in peat swamp forest. An observation hide was built directly under the fig crown and a base camp was built about 100m away from the hide.

Birds and mammals were scanned using binoculars. Animals were counted for 15 minutes (using a timer) followed by a 15 minute break. Two observers were involved in the study which was carried out from 6am to 6pm and 7pm to 6am.

The weather was cloudy during the early morning from 6am to 1145am. A little rain fell from 1200 noon to 1345hrs. The weather was fine, hot and sunny from 1400hrs to 2045hrs. It was clear fine weather from 2100 to 0045hrs.

Human activities
Villagers were clearing forest for rice fields near the study site (but outside the Park) during observations. These activities may have disturbed the larger birds and mammals visiting the fig tree. Under the fig tree there were about 12 old empty cartridge-cases and the undergrowth had been cleared, possibly by hunters to improve their view.

Birds
A huge number (>500) of unidentified small birds were feeding on fig fruits in the early morning from 0600am to 1045am. The first to call at dawn were barbets. The fruiting fig attracted up to 80 barbets feeding at one time.

The fruiting Ficus benjamina also attracted four black hornbills and 105 glossy starlings feeding at one time. Glossy starlings were the most frequently encountered birds throughout the day. A maximum of 66 little green pigeons were counted feeding in the morning.. Hill myna were noisy, but only came in small numbers. Other frugivorous birds encountered included blue-crowned hanging parrots, slender-billed crow and green leaf bird.

A few insectivorous birds were encountered around the fig tree, possibly feeding on insects attracted by the fruit. These included white-rumped shama and spider hunter.

Mammals
Fewer mammals than birds came to feed at the fig tree; the most numerous were a group of twelve long-tailed macaque feeding at one time. Two banded langur were recorded; this is the first record of the species along the northern boundary of Niah National Park (E L Bennett, pers. comm.). The only other mammals encountered during the day were squirrels.

Nocturnal mammals encountered included two common civet, fruit bats including two flying foxes, and a rat feeding on fallen fruits on the ground.

Limitations of the methods
This study was limited in time, covering only one period of 24 hours. It was further affected by rain and nearby human disturbance. It was difficult to identify the animals against the light with the quality of binoculars available. When a large number of birds was present, it was impossible to identify and count them properly in fifteen minutes, but if the time is extended, the number may fluctuate within a single counting period.

Importance of figs
It is often stated that figs are an important food source for frugivorous animals and they are regarded as ‘keystone’ species, but there are few data to back this up. This study shows that Ficus benjamina are used by large numbers of small birds and many other fruit-eating animals. Few big birds and mammals were encountered during the study; this may be because the fruit are relatively small, too small for big animals to feed on, or it may be due to hunting pressure. Furthermore, Ficus benjamina and other figs bear fruit frequently throughout the year, including at times when other trees are not fruiting.

Because of the large numbers of birds congregating at fruiting fig trees, they can be an attraction for bird-watchers and an invaluable resource for nature tourism.

This study shows that Ficus benjamina is a keystone species that supports many small birds and other fruit-eating animals in the forest, playing a very important role in the ecosystem.

There was clear evidence of human disturbance, including clearing and empty cartridge-cases at the foot of the fig tree studied. Because so many animals are attracted to fig trees, steps should be taken to reduce this, especially when they are fruiting. This may mean more patrolling during the fruiting season and closing trails which are little used by visitors.

The sighting of banded langur near the park’s northern boundary is significant because it confirms recent reports that they have appeared in the area.

Good L. (1991) A Management Plan for Niah National Park. Unpublished report for National Parks and Wildlife Division, Sarawak Forest Department.