Black-faced Laughingthrush

The black-faced laughingthrush is a member of the family Leiothrichidae found in the Eastern Himalayas. Its range extends from eastern Nepal eastwards to Arunachal Pradesh in India and further to Myanmar, along with Bhutan and south-eastern Tibet, and small disjunct populations also exist in continental Southeast Asia (Wikipedia, general species account).

That short account is the only source read for the Bhutan guide. It gives no plumage, size, habitat, diet or breeding information, so none is stated.