
Photo: (c) desertnaturalist, some rights reserved (CC BY) · CC-BY (May be cropped or resized)
Pteruthius rufiventer
Habitat
Subtropical or tropical moist montane forests
Range
Eastern Nepal to north-western Vietnam
The black-headed shrike-babbler is traditionally placed with the Old World babblers in the family Timaliidae, though it might be one of the few Eurasian vireos. It is found from eastern Nepal to north-western Vietnam, in subtropical or tropical moist montane forest (Wikipedia, general species account).
That short account is the only source read for the Bhutan guide. It does not name Bhutan specifically, and gives no plumage, size, diet or breeding information, so none is stated.