19. The Feeding Ecology of Edible-Nest Swiftlets in a Modified Landscape in Sarawak

There has been a dramatic establishment of swiftlet houses throughout the state of Sarawak over the last two decades, largely supplanting traditional sources of sought-after birds’ nests. As a result, edible-nest swiftlets have succeeded in expanding their range. This study focused on the feeding ecology of swiftlets in order to clarify their adaptability in a disturbed and modified landscape. Our preliminary survey during the dry season showed that many birds that left their colonies in Bintulu city in the morning flew in the direction of a lower montane area, whereas in the evening they were observed flying back in the direction of their colonies. Swiftlets thus appear to commute between their colonies and their primary feeding grounds that are more than 30 km apart. This is due to high insect availability in the natural forest. Although suburban and rural landscapes may function as secondary feeding areas, our study indicates the importance of natural forests as a primary feeding area. This suggests how edible-nest swiftlets have adapted to the new nesting sites and modified feeding landscapes from the perspective of feeding behaviour.