1262. Erythropus amurensis.
The Eastern Red-legged Falcon.
Tinnunculus vespertinus, apud Blyth, Cat. i, p. 16 ; nec Falco vespertinus, X. Erythropus vespertinus, apud Horsf. & M. Cat. i, p. 14; Jerdon, B. I. i, p. 40; Blyth, Ibis, 1866, p. 238; Stoliczka, J. A. S. B. xxxvii, pt. 2, p. 13 ; Hume, Rough Notes, p. 106; Jerdon, Ibis, 1871, p. 243 ; Legge, S. F. i, p. 487 ; Hume, S. F. iii, p. 22 ; Sharpe, ibid. p. 303; Hume, Cat. no. 19. Falco vespertinus, var. amurensis, Radde, Reis. Siid. O.-Sibir. ii, p. 102, pl. 1. fig. 2 (1863). Erythropus amurensis, Gurney, Ibis, 1868, p. 41, pl. ii: 1882, p. 147 ; Hume, S. F. ii, p. 527 ; iii, p. 327 ; Hume & Inglis, S. F. v, p. 6. Cerchneis amurensis, Sharpe, Cat. B. M. i, p. 445 ; Legge, S. F. iii, p. 362; Hume, Cat. no. 19 bis ; Legge, Birds Ceyl. p. 119; Inglis, S. F. ix, p. 243; Butler, ibid. p. 371; Hume, S. F. xi, p. 5. Tinnunculus amurensis, Oates, B. B. ii, p. 219. Cerchneis vespertina, Hume, Cat. no. 19: Barnes, Birds Bom. p. 20.
Red-legged Falcon, Jerdon.
Coloration. Adult male. Upper parts and tail dark slaty grey, blackish on the head, nape, back, and scapulars, quills washed outside with silvery grey; cheeks sooty black, ear-coverts paler; lower surface from chin to abdomen ashy grey; lower abdomen and under tail-coverts deep ferruginous red; wing-lining and axillaries pure white, lower surface of quills black throughout.
Adult female. Above slaty grey, brownish on the head, nape, and upper back, paler on the rump and tail; feathers of the head and nape dark-shafted, all others, barred with black bands, especially on the rump and tail, subterminal band on tail broader; a cheek-stripe, feathers below the eye, and a band running back from it black; primaries blackish, with oval white spots forming bars on inner webs, except near the tips; lower parts to the abdomen including the ear-coverts creamy white or pale rufous; breast with elongate black spots that pass into arrow-head or heart-shaped markings and bars on the flanks and upper abdomen; lower abdomen and lower tail-coverts rufous, not spotted; wing-lining white with brown spots ; axillaries barred white and dark brown.
Young birds are like the female, but the head is much browner, and the feathers of the mantle have broad rufous borders; there is also an imperfect buff nuchal collar.
Bill fleshy red with a dusky tip, cere deep orange-red, orbital skin orange-yellow; legs deep orange-red, claws flesh-coloured (Jerdon) ; irides hazel (Gurney).
Length of a male 11.5; tail 5; wing 9 ; tarsus 1.1; mid-toe 1 ; bill from gape .75. Females are a little larger on an average.
Distribution. A migratory bird, breeding in North China in summer and wintering partly in India and Burma, but principally in Eastern Africa. This Falcon has been chiefly observed, in India, in Kumaun, Sikhim, Bengal, and Cachar, towards the latter part of the monsoon, when it is migrating southward; only occasional occurrences have been recorded in Pegu, the Western Himalayas, the Deccan, the Nilgiris, the Carnatic, and Ceylon.
E. vespertinus, the European Red-legged Falcon, to which the first few specimens of E. amurensis found in India were referred, is easily distinguished, the male by having a dark grey wing-lining instead of a white one, the female by its rufous head and immaculate breast, and the young birds by having the crown rufous instead of brown. So far as is known the true E. vespertinus has not been found in India.
Habits, &c. The present species is highly gregarious and mainly insectivorous. It migrates in large flocks, which roost together at night. It breeds in China in magpies' nests.