Grey-bellied Bulbul Pycnonotus cyaninventris is a very scarce resident of the lowland primary and secondary forests, swamp, ladang, cocoa and rubber plantation, forest edge and often along rivers. Near threatened (BirdLife International 2001).
Their food consists of green berries and Trema orientalis berries, and insects, usually seen in mixed flocks at fruiting trees with barbets, bulbuls, leafbirds and pigeons . Denis M. Batchelor saw them hawking rising ants or termites. (Rising ants or termites is quite a common event in the early morning after a night or few nights of rain, winged reproductive forms of ants or termites are seen flying out from the nest hole in the ground in large swarms, such swarming behavior is usually synchronized by other nearby colonies so large numbers of winged ants suddenly appear, attracting numerous feeding birds catching them on the wings. I witnessed Asian Glossy Starling Aplonis panayensis, White Breasted Woodswallow Artamus leucorynchus, Eurasian Tree Sparrow Passer montanus, Java Sparrow Padda oryzivora and Chestnut Munia Lonchura atricapilla feeding on them as they flew out form their nest hole in front on my home. No doubt the composition of the predating birds would be different in the forest setting.)
Two birds were photographed in Tawau, saw them flew in to feed on tiny black ants on the tree trunks, the ants are visible in the second photograph.
This is my new bird and bring my count of photographed wild birds of Borneo to 311.
Photodocument of Wild Birds of Borneo