This taxon is Not Recognised as a species by BirdLife International.
Zoothera major, Z. dauma and Z. horsfieldi (Sibley and Monroe 1990, 1993) have been lumped into Z. dauma following Collar (2004). Z. imbricata from Sri Lanka, previously considered a subspecies of Z. dauma following Sibley and Monroe (1990, 1993), is treated as a distinct species following Rasmussen and Anderton (2005).
BirdLife International (2016) Species factsheet: Zoothera major. Downloaded from http://www.birdlife.org on 07/12/2016. Recommended citation for factsheets for more than one species: BirdLife International (2016) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 07/12/2016.