(606) Monticola cinclorhyncha.
The Blue-headed Rock-Thrush.
Petrocincla cinclorhyncha Vigors, P. Z. S., 1831, p. 172 (Himalayas, Simla). Petrophila cinclorhyncha. Blanf. & Oates, ii, p. 144.
Vernacular names. Krishen-patti (Nepal); Daohangar, (Cachari); Vohtigle (Mikir); Hengmeruine (Kacha Naga).
Description.— Adult male. Crown, nape, chin, throat and lesser wing-coverts bright cobalt-blue; a narrow line above the eye, lores, cheeks, ear-coverts, sides of neck, back and scapulars black; greater wing-coverts and winglets black edged with blue; primaries black, all but the first two edged with blue ; secondaries black, all but the innermost with a broad white band on the base of the outer webs; tail blackish edged narrowly with blue; rump, upper tail-coverts, whole lower surface, axillaries and under wing-coverts chestnut.
Colours of soft parts. Iris dark brown; the gape yellow and in the non-breeding season the base of the lower mandible also yellowish ; legs and feet plumbeous or plumbeous horny, the claws blacker.
Measurements. Total length about 180 to 190 mm.; wing 100 to 104 mm.; tail 65 to 68 mm.; tarsus 24 to 25 mm.; culmen 18 to 19 mm.
Female. Whole upper plumage, wings and tail olive-brown, tinged with ochraceous on the rump and upper tail-coverts, which are barred with dull black; the tail is faintly cross-rayed and the feathers of the wings edged paler; below white tinged with fulvous on breast and flanks, the chin and throat nearly immacu¬late, the remainder barred with dark brown; under wing-coverts and axillaries pale fulvous barred with blackish ; under tail-coverts white with black lines following the contour of the feathers.
Colours of soft parts. Iris brown; bill dark horny-brown, paler at the base ; legs horny-brown or slaty-brown.
Measurements. Wing 93 to 105 mm.; tail 65 to 09 mm. The male in Winter has the feathers of the black parts broadly fringed with fulvous.
Nestling. Like the female but with the whole upper plumage golden fulvous, each feather edged with blackish.
Young males are like females but from a very early age show the blue on wings and tail.
Distribution. From the Afghan and Baluchistan frontiers throughout the Himalayas to East and South Assam, the Chin Hills and Kachin Hills. In winter it spreads practically throughout India and West and Central Burma.
Nidification. The Blue-headed Bock-Thrush breeds throughout its Northern range between 4,000 and 9,000 feet, most often between 4,000 and 6,000 feet. Nest and eggs are exactly similar to those of the preceding bird except in size. Fifty eggs average 23.7 x 17.9 mm.: maxima 27.1 x 18.6 and 23.6 x 20.0 mm.; minima 21.3 x l9.9 and 23.6 x 16.9 mm. They commence to breed in early April and throughout May to the middle of June, but I have seen odd nests with "eggs in July and August, probably second broods.
Habits just the same as those of M. erythrogastra.
Turdus solitarius P.L. S. Muller, S. N. Anhang, p. 142 (1776) (Italy).
The Bock-Thrush has been split up into many subspecies, some of which are differentiated by characters which are hardly discernible and others by such as are very well marked. The extreme Eastern bird from China to the Philippines is marked by the whole red under parts from breast to under tail-coverts, whilst the extreme Western bird is all blue. Both of these have been split up into various races based on a very small degree in depth of colour etc., but the intermediate race, winch contains the characters of the two extremes, has been ignored since the time of Blyth. The area of this form embraces all Burma, Siam and the Indo-Chinese countries and it would be silly to imagine that we have hybrids extending over so vast an area and, even though the individuals vary much in details of coloration, it seems wiser to accept them as a race intermediate in coloration, as in country, between the two extremes.
Key to Subspecies.
A. All blue both above and below.
a. Paler above and below M. s. transcaspica, p. 173
b. Darker above and below M. s. pandoo, p. 174.
B. Under tad-coverts and often the
abdomen and flanks marked with
chestnut .. M. s. affinis, p. 175.
C. From breast to under tail-coverts
uniform chestnut M. s. philippensis, p. 175.