We present the most comprehensive list of birds for the upper Siang region based on surveys and opportunistic observations from 2010 to 2016. Of the 252 species recorded for this region, we report 66 for the first time, including six globally threatened species. The presence of migratory waterfowl indicates the importance of the Siang Valley as a migratory route. We also emphasise the importance of mixed-use shifting cultivation landscapes outside protected areas in sustaining bird diversity. Further focused surveys in remote parts of this landscape are required to fully understand the biodiversity significance of this region in the face of emerging large-scale threats.