(480) Cinclus pallasii marila.
The Formosan Brown- Dipper.
Cinclus marila Swinhoe, Ibis, 1860, p. 187 (Formosa).
Vernacular names. Di-dao-bui (Cachari).
Description. Similar to the Indian Brown Dipper but darker everywhere. Both this and the last bird differ from C. p. pallasii in being less deep a chocolate in colour. This race is distinguish¬able from C. p. soulei in being a trifle paler.
Colours of soft parts. Iris hazel to dark brown; bill black; legs and feet horny-brown, plumbeous-brown or almost black; soles always paler and yellowish or fleshy.
Measurements. Wing 96 to 116 mm.; culmen 20 to 22*5 mm. The same measurements in C. p. soulei are 108 to 115 and 23 to 24 mm. respectively. I cannot divide Formosan birds from those of China, Burma and Assam. In the British Museum collection there is one Formosan, one Burmese and one Chinese bird, each with a wing of 116 mm. and several Assam specimens with wings of only 96 and 98 mm.
The young bird differs from that of the Indian Brown Dipper in being much darker; the grey above is replaced with brown and the dark centres to the feathers are larger; the lower plumage is brown, each feather with broad white edges.
Distribution. At present not well defined. Formosa, whence it was described by Swinhoe; Shan States (Harington); Chin Hills (Mackenzie) and the mountains South of the Brahmaputra River. Probably it will be found to be a small, low-level form of O. p. soulei extending all through the Burmese and Indo-Chinese Hill country. It has also been killed at Kuatun.
Nidification. In the Khasia and North Cachar Hills the normal breeding season is December to February, before the streams begin to fill up, but many birds lay in early April and even in May, though these latter place their nests in such positions that they are generally washed out in the first rains of June. I, however, took one nest with eggs as late as July, evidently the production of birds which had had their first attempts destroyed. The early nests are all placed on boulders, fallen trees or piles of debris lying in mid-stream or on rocks actually under waterfalls, through which the birds have to pass to the nest. The later nests are more often placed on the banks and cliffs above the rivers. They are huge affairs, often over a foot long by eight or ten inches wide and, when one knows what to look for, very conspicuous. To the casual observer, however, they look only like masses of moss and leaves left by a falling -flood. The eggs number four or five and are just like other Dippers' eggs. Thirty eggs average 26.7 x 18.9 mm.: maxima 28.5 X 19.2 and 27.0 X 20.0 mm.; minima 24.3 x 18.3 and 26.0 x 17.7 mm.
Habits. This Dipper is very common in the Khasia Hills although not so very often seen, for it keeps very closely to streams which pass through woods, each pair apparently haunting its own stretch of water. Occasionally its sharp cry may attract one's attention on some open piece of river or stream as it flits hurriedly from one cover to another, especially in late autumn when the rivers and streams are running low. At this season and before nesting commences, it seems less secretive but it is always a shy, wild bird and most difficult to watch. It lives almost as much under water as above it and feeds on tiny fish, insects, tadpoles and water spiders, in catching which it displays most extraordinary activity.