I took the opportunity of a trip to Tibow, Sapulut -- a place in the heart of Sabah, not far from the Indonesian border--to ascertain what "open-country" birds have managed to establish themselves in an open area surrounded by secondary forest and accessible only by road. Results showed that 10 resident species of open-country birds have established themselves and the area is being used by several open-country migratory species. The survey was made over 5 full days 4/4/00 to 10/4/00.
Tibow was extensively logged between 1978 and 1990 and almost all large trees were removed, Koompassia excelsa being a significant exception. It remains forest however, and the area has not been logged in the past ten years. A dirt logging road connects the area to both east and west coastal towns. The nearest open country (extensive oil palm estates) is about 100 kms away, accessible only by the single road wide enough to handle logging trucks through secondary forest. The area round the Forestry Department office was opened up in 1978 and consists of scattered houses, offices, workshops and playing field. It covers about 3 hectares of open ground surrounded by secondary forest and connected to the main road 0.8kms away by a dirt road. Several ponds and streams border the area.
This area presented an opportunity to discover which open country birds have managed to colonize the suitable habitat or to use the area while on migration, in spite of its isolation. Twelve species were identified that were wholly open-country species, not known to make use of forest habitats on any sustained basis:
- WHITE-BREASTED WATERHEN Amaurornis phoenicurus -- common
- *COMMON SANDPIPER Actitis hypoleucos -- one bird seen -- still present on the 10/4 -- foraging on the playing field.
- LESSER COUCAL Centropus bengalensis -- common (Greater Coucal also present)
- PACIFIC SWALLOW Hirundo tahitica -- common
- YELLOW-VENTED BULBUL Pycnonotus goiavier -- seen nesting .
- ORIENTAL MAGPIE ROBIN Copsychus saularis -- common. Seen bringing food to nest in an epiphyte fern growing at the top of a lamp post -- with lamp just above nest.
- YELLOW-BELLIED PRINIA Prinia flaviventris
- RICHARD'S PIPIT Anthus novaeseelandiae -- several pairs on the playing fields
- *BROWN SHRIKE Lanius cristatus -- one seen 4/4 but not thereafter.
- BROWN-THROATED SUNBIRD Anthreptes malaccensis -- very common. One young seen being fed out of nest.
- EURASIAN TREE-SPARROW Passer montanus -- common
- DUSKY MUNIA Lonchura fuscans -- several small flocks
Two migratory species (marked with an asterisk) and the annual presence of a third (a flock of unidentified egrets, as reported by forestry officers), indicate that migratory species are able to take opportunistic advantage of clearings where none were present in the past and can be assumed to be capable of traversing forest in long flights.
The others are more likely to have followed the road in, breeding and expanding the population over a period of years. Numbers were sufficient to indicate that they have viable breeding populations; three species were in fact seen to be breeding.
Two species which might have logically have been expected, the Philippine Glossy Starling Aplonis panayensis and the Chestnut Munia Lonchura malacca, both present along the coast, were not found. Other open country species common in more settled coastal areas were also not present e.g. Common Iora, Olive-backed Sunbird, Large-tailed Nightjar, Spotted Dove. The road edge between the coast and Tibow does perhaps not supply sufficient habitat for all these birds to thrive and thus reach Tibow. The Olive-backed Sunbird, for example, does not make use of forest edge as does the Brown-throated Sunbird, present in Tibow in abundance. However even two species capable of dispersal over forest, the House Swift and the Blue-throated Bee-eater were also absent.
My thanks is extended to the Forestry Department Sabah, especially the Tibow office; and to Dr Chey of the Sepilok Forest Reserve and to Prof. Mohamed Salleh Mohamedsaid of the Pusat Sistematik Serangga, University Kebangsaan Malaysia, for including me in their entomological survey team of the area.