Fire-capped Tit

The fire-capped tit is a small tit, 10cm long and weighing about 7g, that breeds in temperate forest bordering the Himalayas to the south and in several ranges of western China, and winters downhill and further south. Outside the breeding season the crown is dark olive-brown and the upperparts yellowish to olive-green, while in breeding plumage the male has a slight orange-scarlet crest (Wikipedia, general species account).

Calls include a high-pitched, jerky 'tsit-tsit-tsit-tsit' and a soft, low 'whitoo-whitoo'. During migration and in winter it is usually found in small flocks, though groups of up to 100 may be seen. There are usually four dull blue-green eggs, and the incubation period is unknown. The source read does not name Bhutan, so its occurrence there is flagged for checking.