
Photo: J.M.Garg · CC BY-SA 3.0 (May be cropped or resized)
Saxicola ferreus
Habitat
Subtropical or tropical moist lowland and moist montane forest
Range
The Himalayas, southern China, Taiwan, Nepal and mainland Southeast Asia
The grey bush chat is a passerine of the Old World flycatcher family found in the Himalayas, southern China, Taiwan, Nepal and mainland Southeast Asia. Its natural habitats are subtropical or tropical moist lowland forest and 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.