(1795) Circus spilonotus.
THE EASTERN MARSH-HARRIER.
Circus spilonotus Kaup. in Jard. Con. Orn., p. 59 (1850) (Asia, Philippines): Blanf. & Oates, iii, p. 388.
Vernacular names. Thane-kya (Burmese).
Description. Crown and sides of head and neck and upper back white to pale buff broadly streaked with blackish-brown ; back, scapulars and inner wing-coverts dark brown with white or rufous spots at the tips of both webs; rump brown, the broad white bases showing everywhere; upper tail-coverts white with pale grey bands following the contour of the feathers; tail-feathers silvery grey, tipped and mottled on the inner webs of the outer tail-feathers with white ; first five primaries blackish with mottled white bases; sixth primary grey and blackish ; remaining quills, greater and outer median coverts grey with paler tips and broad black subterminal patches ; lower plumage white, broadly streaked on the throat and breast with blackish, immaculate or finely streaked elsewhere.
Colours of soft parts. Iris golden-yellow, bill deep slaty-black at the tip and yellowish at the base and gape; cere dull yellow; legs and feet pale yellow.
Measurements. , wing 384 mm.; tail 224 mm.; tarsus 91 mm.; culmen 29 mm. . wing 406 to 420 mm.; tail 244 to 256 mm.; tarsus 91 to 95 mm.; culmen 31 to 32 mm.
Female. Very like that of the Marsh-Harrier but with the feathers of the crown, nape, neck and upper back pale rufous or buff with broad streaks of dark brown; the scapulars and wing-coverts also have more or less rufous tips and edges; the upper tail-coverts are mixed rufous, grey and white ; central tail-feathers dark brown with pale tips and lighter cross-bands, outer feathers with no bands, paler and mottled on the inner webs with fulvous or buff; below as in C. aeruginosus but much more marked with fulvous or buff, the lower breast being nearly all buff; the chin and throat are buff with fine black shaft-lines.
Young birds are like those of the Marsh-Harrier but are more streaked above; the central tail-feathers have six dark bars and the outer tail-feathers are pale rufous with whitish tips and four pale brown bars, the darkest next the tip.
Distribution. Transbaikalia to Tibet and Western China. In Winter South to South China, the Indo-Chinese countries to the Philippines. I obtained several in Cachar, Hume saw it in Manipur and it has been obtained near Moulmein.
Nidification. The Eastern Marsh-Harrier breeds during May and June, making a nest similar to that of the Marsh-Harrier. It lays three to six eggs, the former number probably being incomplete. They are white so far as is known and twenty-eight average 48.7 x 37.2 mm.: maxima 60.0 x 38.5 and 55.0 x 41.0 mm.; minima 41.0 X 34.4 and 42.0 x 33.5 mm.
Habits. Similar to those of the preceding bird.