(2093) Sterna anaetheta anaetheta.
THE PHILIPPINE BROWN-WINGED TERN.
Sterna anaetheta Scopoli, Del Flor. et Faun., Insubr., ii, p. 92 (1786) (Philippines). Sterna anaestheta. Blanf. & Oates, iv, p. 323 (part.).
Vernacular names. None recorded.
Description. Forehead and short supercilium white; lores, crown, nape and behind the eye black; hind-neck pale grey; edge of wing-coverts white next the back ; mantle, tail and wings dark brown; coverts next the white edge to the wing and primaries blackish, the latter with white centres to the inner webs of the first three, very conspicuous and contrasting with the dark brown ; outermost tail-feathers white on all but the terminal half of the inner web ; sides of head and lower plumage white, sometimes slightly washed with grey on the breast and abdomen and flushe with pale rosy in the breeding-season.
Colours of soft parts. Iris dark brown; bill, legs and feet black.
Measurements. Wings 242 to 261 mm.; tail 156 to 184 mm.; tarsus about 22 to 23 mm.; culmen 41 to 45 mm.
In Winter the upper plumage is less grey, whilst the crown is brown with white edging to the feathers.
Young birds have the upper plumage a paler brown, each feather edged broadly with white ; the black band from the lores is replaced with white speckled with black; the crown is brown with greyish edges to the feathers, the nape being almost all brown.
Distribution. Celebes, Philippines and islands off: the Chinese coast to the Gulf of Siam and casual round the coast of the Malay Peninsula to Mergui, where, however, the usual form which occurs seems to be antarctica.
Nidification. This Brown-winged Tern breeds on many small islands throughout its habitat during May and June. Williamson found a colony breeding on the 6th of May, on a small rocky island, in Chalan, in the Gulf of Siam, the birds laying their single eggs in depressions scratched among the coarse grass which grew everywhere it could obtain root-hold on the upper part of the island. The eggs he obtained are very beautiful and vary greatly. In a series of twenty-four they range from pure pale unspotted blue to deep salmon-buff with bold blotches of blood-red. Others have a pale cream or yellowish ground finely speckled and spotted with light red. The series averages 46.5 x 32.3 mm.: maxima 47.8 x 32.5 and 43.5 x 34.2 mm.; minima 43.5 x 34.2 and 47.5 x 31.0 mm.
Habits. The Brown-winged Terns are all strictly Sea-Terns, often being found far away from land and not uncommonly taking a rest on passing ships. Their flight is easy and graceful and they alight on the water more frequently than most Terns. Their food consists of small fish and Crustacea, such as are obtained in deep water, except in the breeding-season, when they subsist in great part on shrimps and shallow-water fry. Their call is a rather hoarse " krek."