Cinereous Tit

The cinereous or Asian tit was formerly treated as a subspecies of the great tit. It is grey-backed with white underparts, a black hood, a white cheek patch, a white wing-bar and a broad black stripe along the centre of the underside, with no crest. Young birds can show some green on the back and yellowish on the underparts (Wikipedia, general species account).

The birds are usually seen in pairs or small groups that sometimes join mixed-species foraging flocks, and calling is particularly persistent in the breeding season. The normal clutch is about four to six eggs, and both parents incubate, hissing from within the nest when threatened. The source read does not name Bhutan, so its occurrence there is flagged for checking.