Taking into account speciation patterns within Otus and general phylogeographic patterns of montane birds on Borneo and Sumatra, both subspecies likely represent two distinct species; taxonomic studies will be required to confirm or deny this claim.
Given the observed divergence within Otus and the general patterns of bird migration on mountainous islands like Borneo and Sumatra, it is probable that the two subspecies constitute distinct species; a thorough taxonomic examination will be needed to confirm or disprove this hypothesis.