The birds had been identified as Pale-bellied Myna Acridotheres cinereus, an endemic species of Southern Sulawesi. They could have been introduced here as caged birds.
They have been here for a number of years now. A visit recently showed that they are doing very well, I saw about 40 to 50 birds on a bare tree, flocking with some Asian Glossy Starling Aplonis panayensis and a darker individual suspected to be a Javan Myna Acridotheres javanicus.
Here are the pictures.
The darker bird in the middle is suspected to be a Javan Myna.
Photodocument of Wild Birds of Borneo
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