(1775) Butastur liventer.
THE RUFOUS-WINGED BUZZARD-EAGLE.
Falco liventer Temm., Pl. Col., lxxiv, pi. 438 (1827) (Java). Butastur liventer. Blanf. & Oates, iii, p. 364.
Vernacular names. None recorded.
Description. Head, neck and upper back ashy-grey, tinged with brown in younger birds, the shafts darker 5 back and wing-coverts ashy-brown, tinged with rufous and becoming darker and more rufous on the upper tail-coverts and rump; tail deep rufous, tipped pale ashy, a subterminal band of blackish and two or three narrow incomplete bars of black; edge of wing white; outer coverts and primary coverts rufous tipped with brown; quills bright rufous-chestnut, tipped and edged outwardly with brownish, broadly white on the basal edges of the inner webs and with narrow bars of black; innermost exposed secondaries like the back; lower parts ashy-grey, more or less tinged with brown and with faint dark shafts, vent and under tail-coverts pure white or buffy-white; abdomen intermediate and showing traces of the juvenile barring.
Colours of soft parts. Iris yellow, sometimes golden yellow ; bill yellowish-horny, black at the tip ; cere and gape yellow ; legs and Feet dull yellow, claws black.
Measurements. wing, 261 to 275 mm.: tail 139 to 145 mm,: tarsus 62 to 66 mm.; culmen 28 to 31 mm. wing 264 to 280 mm.
Young birds have the head and neck above brown or rufous-brown with pale edges; the forehead is paler and there is a distinct whitish supercilium ; upper parts generally darker and more heavily streaked with blackish; wing-coverts much mottled and barred with whitish; chin and throat white, brown at the sides ; lower parts pale grey with fine black shafts and faint white bars; thigh-coverts, vent and under tail-coverts white.
Distribution. Throughout Burma from the Chin and Kachin Hills to Southern Tenasserim ; Shan States, Siam and Yunnan ; Borneo, Java and Celebes.
Nidification. Oates and Fielden found this Buzzard-Eagle breeding in March in Pegu, Harington and Grant took newts and eggs in April in the Kachin Hills and Wickham found it breeding commonly in the Southern Shan States in March and April. Nest and eggs exactly resemble those of Butastur teesa. The former is built in trees in thin forest or in trees standing in the open. The average of eleven eggs is 46.3 x 37.8 mm.: maxima 48.7 X 37.1 and 46.6 x 40.0 mm.; minima 44.2 X 36.8 and 45.6 x 36.5 mm.
Habits. Similar to those of the preceding bird, freshwater crabs are said to form a large part of its diet and therefore its resorts are principally the banks of the large rivers but Wickham also found it frequently in the interior of thin deciduous oak forests in the Shan States,