“Young (in August).—Mantle barred and mottled with ash-brown; outer webs of tail-feathers dark gray; band on wing-coverts more extended than in the immature bird; otherwise similar. In fledglings the upper parts are much marked with warm buff.
“Up to about the end of September the colors of bill and feet become lighter, but afterwards they rapidly go back and become more or less horn-colored.
“Nestling.—Forehead and throat brown; upper parts stone-buff, spotted and streaked with black; under parts white; feet yellow.” (Saunders.)
79. STERNA LONGIPENNIS Nordmann.
NORDMANN’S TERN.
- Sterna longipennis Nordmann, in Erman’s Reise (1835), 17; Saunders, Cat. Birds Brit. Mus. (1896), 25, 67; Blanford, Fauna Brit. Ind. Bds. (1898), 4, 319; Sharpe, Hand-List (1899), 1, 135; Oates, Cat. Birds’ Eggs (1901), 1, 185, pl. 14, fig. 4.
Basilan Straits (Mearns). Eastern Siberia, Kamtchatka, and Japan; in winter China to New Guinea.
“Coloration.—Similar to that of S. fluviatilis [= hirundo], except that the bill is always black and the feet are blackish. Adults are darker in color, both above and below, but the difference is not great. All the measurements appear identical, or nearly so, except those of the bill, which is altogether smaller, and measures about 45 mm. from the gape.” (Blanford.)
“Adult in winter.—Forehead flecked with white otherwise similar.
“Immature.—Like that of fluviatilis [= hirundo] from which it can hardly be distinguished except by the color of the bill and feet and the somewhat smaller size and more delicate shape of the latter.” (Saunders.)