1553. Anastomus oscitans.
Ardea oscitans, Bodd. Tabl. Pl. Enl. p. 55 (1783). Anastomus oscitans, Blyth, Cat. p. 276; Irby, Ibis, 1861, p. 244; Jerdon, B. I. iii, p. 765; Blyth, Ibis, 1807, p. 173; Hume, N. & E. p. 630 ; id. S. F. i, pp. 107, 133; Ball, S. F. ii, p. 435 ; Blyth, Birds Burm. p. 158; Butler & Hume, S. F. iv, p. 25 ; Bingham, ibid. p. 211 ; Fairbanh, ibid. p. 264; Murray, S. F. vii, p. 110; Putter, ibid. pp. 188, 189 ; Ball & Hume, ibid. p. 231 ; Cripps, ibid. p. 310; Doig, ibid, p. 467 ; Hume, Cat. no. 940; Legge, Birds Ceyl. p. 1103; Butler, S. F. ix, p. 435; Reid, S. F. x, p. 77; Davidson, ibid. p. 324; Davison, ibid. p. 417; Oates, B. B. ii, p. 266; Barnes, Birds Bom. p. 389 ; Hume & Cripps, S. F. xi, p. 338; Oates in Hume's N. & E. 2nd ed. iii, p. 224; Barnes, Jour. Bom. N. H. Soc. vi, p. 151; Sharpe, Cat. B. M. xxvi, p. 306.
The Shell-Ibis, Jerdon; Gungla, Ghongal, Ghonghila, H.; Dokar, H. (Behar) : Tonte-bhanga, Shamakh-bhanya, Samak-khol, Hammak-kas, Beng.; Pauna konga, Southern Gonds; Galu Konga, Tel.; Nattt kuti nareh, Tam.; Karunary, Tam. (Ceylon); Gombelle-koka, Cing.; Kha-ru-tsoke, Burm. (Arrakan).
Coloration. In breeding-plumage the longer scapulars, all the quills, the winglet, primary and greater secondary coverts, and the tail are black, glossed with dark green and purple ; remainder of plumage white.
At the moult after the breeding-season the white is replaced by smoky grey, darkest on the occiput and upper back. This becomes white by a change of colour in the feathers at the breeding-season. The black parts of the plumage undergo no change.
Young birds have the back and shorter scapulars brown, longer scapulars and tertiaries brownish ; otherwise they resemble adults in non-breeding plumage.
Bill dull greenish, tinged with reddish beneath ; nude orbits and gular skin blackish; irides grey or pale brown; legs pale fleshy (Jerdon).
Length 32; tail 7; wing 16.5 ; tarsus 5.5 ; bill from gape 6.
Distribution. Throughout the great plain of Northern India from Bengal to Sind; particularly common in Bengal, and in other well-watered tracts throughout India and Ceylon, but this bird is not common except about large rivers or marshes. It is also common in Assam and Manipur and is found in Arrakan, but is very rare in Pegu and unknown elsewhere in Burma. It occurs, however, in Cochin China.
Habits, &c. This curious Stork lives chiefly on freshwater mollusca, especially Ampullaria, and, it is said, Unto, and is stated by Jerdon, from his observations on captive and blinded birds, to cut off the operculum of the Ampullaria and extract the animal whole; but Bingham, who had good opportunities of watching the birds, both in the field and in confinement, found that they broke the Ampullariae before extracting the molluscs, and crushed smaller mollusca before swallowing them. They occasionally eat fish, crabs, &c, but subsist mainly on mollusca. Anastomus is often seen in flocks, frequenting marshes and paddy fields. It breeds on trees gregariously and lays from 2 to 5, generally 4, white eggs, measuring about 2.24 by 1.6. The breeding-season is July and August in Northern India, January to March in Ceylon.
The name Shell-Ibis being inapplicable to a bird that is a Stork and not an Ibis, I have adopted the term Open-bill proposed by Professor Newton. It is a translation of Button's Bee ouvert, the oldest name for this bird in a European language.
* As Legge has pointed out, signs of wear are confined to the lower mandible, the thick rhamphotheca of the upper mandible and the lamellae show no signs of attrition ; moreover the space does not exist near the gape, where the greatest crushing-power can be exerted.