Description. A black streak over the eye from lores to nape; lores grey or fulvous-brown; sides of head olivaceous or rufous; upper tail-coverts chestnut, remaining upper plumage rufescent olive-brown, each feather with a terminal lunate black tip; in birds which have the lores and sides of the head olivaceous the crown is ashy; wing-coverts chestnut, dusky internally; primary-coverts dusky edged with black; outer web of outer primaries pale blue, inner primaries black; secondaries chestnut at the base; remainder of wing black, the later quills minutely tipped white; lower plumage fulvous, each feather with a terminal black bar; under tail-coverts and thighs castaneous.
Birds with grey crowns have the tail deep black, the others have it bronze-colour with a chestnut tip.
The variations in colour seem due to neither sex nor age. I have found all in both sexes and in pairs breeding together, and they appear to form one of those curious dimorphic colorations, the necessity for the evolution of which naturalists have not yet been able to detect.
Colours of soft parts. Legs and feet pale flesh to fleshy-brown; bill horny black, paler and greyer at tip and on base of lower mandible; iris pale greenish or bluish white; glaucous-brown or dull brown, these latter probably only in young.
Measurements. Length about 250 to 260 mm.; wing 93 to 99 mm.; tail about 100 mm.; tarsus about 37 mm.; culmen about 20 mm.
Distribution. The Himalayas from Nepal to the Kachin Hills; hill-ranges North of the Brahmaputra to N. Arrakan, and Chin Hills and Shan States.
Nidification. The bird breeds at all heights between 3,000 and 6,000 feet and in Nepal (vide Hodgson) as low as 2,000. The nest is the usual bulky cup in shape, fairly compact, and made principally of dead leaves intermixed with roots, tendrils and grass, and lined with roots. It is always placed low down in some thick bush or tangle of creepers, often within a foot or two of the ground. The eggs, two or three in number, are spotless blue-green, the texture very smooth and fine but soft and almost glossless. Fifty eggs average 29·4 × 20·7 mm.
Habits. The Blue-winged Laughing-Thrush is a bird of humid forests at a comparatively low level. In the hills South of the Brahmaputra it is most common between 3,000 and 5,000 feet, and seems to haunt the banks of streams and rivers far more than the other species of this genus do. It goes about both in pairs and in small family parties, and is conversational rather than noisy, many of its notes being very rich and full. Its flight is very weak and ill-sustained, but it is as strong and clever on its feet as the rest of the family.
