(2082) Sterna repressa.
THE WHITE-CHEEKED TERN.
Sterna repressa Hartert, Nov. Zool., 1910, p. 288 (Persian Sea). Sterna albigena. Blanf. & Oates, iv, p. 317.
Vernacular names. None recorded.
Description. Upper parts of head including upper lores but not running under the eye black; upper plumage dark ashy-grey, rather paler on the upper tail-coverts and tail; first primary nearly black on the outer and inner web with a broad white edge to the latter, succeeding primaries silvery grey, the inner webs finely edged whitish, subedged black and paler next the black; chin and cheeks pure white, shading into pale vinous-grey on the throat and sides of the neck and to darker vinaceous on the breast,, abdomen and posterior flanks ; under wing-coverts, tail-coverts and axillaries white.
Colours of soft parts. Iris brown; bill dark blood-red at the base, black on the terminal half with a microscopic pale tip ; legs and feet bright red.
Measurements. Wing 227 to 254 mm.; tail 124 to 154 mm.; tarsus about 19 to 21 mm.; culmen 36 to 38 mm.
In Winter the head is white, the feathers round the eye, nape and upper hind-neck more or less black or chocolate-brown; lower hind-neck and lower plumage white.
Young birds have the quills darker brown, the upper parts mottled with brown ; hind-neck and lower plumage white. Young birds in first plumage have not been described.
Distribution. Sea coasts from the Red Sea and Persian Gulf to Ceylon and the Laccadives.
Nidification. Miss Jackson found the White-cheeked Tern breeding during August on Kiemboni Island, East Africa but in the Persian Gulf Sir Percy Cox and others obtained eggs in May and June. The hollows for the eggs are scratched in sand and occasionally a few scraps of twig are placed as a lining, at other times they are just laid on the bare rock. The eggs number one or two, more often the former. In shape they are broad blunt ovals, though not so broad as those of either of the two preceding species. The ground-colour is a pale stone or yellowish-grey in nine eggs out of ten, with small specks and spots of pale reddish to dark reddish-brown with underlying spots of neutral tint. A few eggs have a pale salmon or butt' ground and still fewer brown or dark buff. A series collected by Miss Jackson are noticeable on account of their bold marking with deep brown blotches and spots. One hundred eggs average 40.8 x 30.4 mm.: maxima 45.3 X 28.2 and 43.9 x 33.7 mm.; minima 37.0 X 28.1 and 40.0 x 28.0 mm.
Habits, The White-cheeked Tern is extremely common throughout its breeding habitat and in the Winter it occurs frequently on the West coast of India as far as Malabar. Off the Mekran coast and Sind it is common and resident, breeding on the adjacent islands. It is essentially a sea-bird, often being met with at great distances from the nearest land.