The island of Siberut is the largest of the Mentawai Archipelago, which lies 125145 km from the coast of mainland West Sumatra. Primary lowland rain forest and freshwater swamp forest cover is extensive on Siberut, and supports a unique fauna with high levels of endemism, the most studied examples of which are the four endemic species of primates. The Mentawais also have an endemic species of Scopsowl Otus mentawi as well as 12 other birds endemic at the subspecific level. Unlike the primates and other mammals however, the avifauna has been poorly studied and its ecology is not well understood. Information is provided on bird surveys carried out between August 1997 and March 2000 whilst the author lived and worked on the island for the Sibe...