Chestnut-backed Scimitar-Babbler is split into two species based on differences in plumage, vocalizations. and habitat/elevation (Eaton et al. 2016). Therefore the polytypic group Chestnut-backed Scimitar-Babbler (Sunda) Pomatorhinus montanus bornensis/occidentalis, with subspecies bornensis and occidentalis, becomes Sunda Scimitar-Babbler Pomatorhinus bornensis; and the polytypic group Chestnut-backed Scimitar-Babbler (Javan) Pomatorhinus montanus montanus/ottolanderi, with subspecies montanus and ottolanderi, becomes Javan Scimitar-Babbler Pomatorhinus montanus.