1497. Hydrochelidon leucoptera.
The White-winged Black Tern.
Sterna leucoptera, Meisner & Schinz, Vog. Schweiz, p. 264 (1815). Hydrochelidon leucoptera, Boie, Isis, 1822, p. 503; Hume, Ibis, 1870, p. 436 ; id. S. F. vii, p. 445 ; id. Cat. no. 984 bis ; id. S. F. viii, p. 495; Legge, Birds Ceyl. p. 1000; Oates, B. B. ii, p. 420; Saunders, Cat. B. M. xxv, p. 6. Hydrochelidon nigra, apud Jerdon, B. I. iii, App. p. 875 ; nec Sterna nigra, L. Sterna nigra, apud Holdsworth, P. Z. S. 1872, p. 481.
Coloration. In winter plumage this Tern is scarcely distinguishable from H. hybrida, except by size. Young individuals of the present species may generally be recognized by their white upper tail-coverts, and adults by their smaller and darker bills.
In breeding-plumage the whole bead and neck, the back and lower parts to the vent, including the wing-lining, are black; scapulars blackish grey; tertiaries dark grey: coverts and quills paler grey (the first two or three primaries generally brownish black), and the smaller coverts on the edge of the wing white ; rump, upper and lower tail-coverts, and tail white, in many birds, probably immature, the tail-feathers are ashy or pearly grey, especially towards the tips.
Bill livid red in summer, reddish black in winter and in young birds ; irides dark brown ; legs vermilion.
Length 9.5 ; tail 2.8 ; wing 8.25; tarsus .75 ; bill from gape 1.3.
Distribution, Temperate Europe and Asia, south of lat. 55° N., in summer, Africa to Australia in winter. This Tern has not been clearly identified from any part of India west of Tipperah, whence a specimen was sent to Mr. Hume, but it has been several times shot in Ceylon; Oates found it common at the mouth of the Sittang, in Burma, and a skin was sent from South Andaman by Mr. de Roepstorff.