Often treated as conspecific with H. castanonotus and H. cinereus (and by extension also H. connectens), but morphological and vocal distinctness of constituent taxa suggests that they are best viewed as separate species; full review necessary to determine relationships. Isolated race remotus is notably divergent, differing in its pale dull brown upperparts with slightly darker crown (3) and possibly rather less strong yellow edgings on wings (1), but brown tinge to breast mentioned in HBW is not apparent; no obvious differences in voice discernible from limited available recordings. S Myanmar–W Thailand race hildebrandi said also to occur in N Vietnam#R, range thus being divided into two by bourdellei; further research needed. Five subspecies provisionally recognized.
Food and feeding
Status and conservation
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