Siquijor (Bourns & Worcester). Tropical and juxtatropical seas of the world.

“Adult in breeding plumage.—Similar to S. anæstheta; but larger, white frontal-band and superciliary stripe broader, the latter oblique and not reaching beyond eye, from which it is separated by a narrow continuation of the black loral stripe; upper surface sooty black, the wedges on inner webs of primaries a trifle paler than the rest; streamers dull white on the outer webs, remaining tail-feathers sooty black; under tail-coverts, abdomen, and flanks grayish white; breast and throat white. Bill and feet black with a slightly reddish tinge, the web between middle and inner toe nearly full, and far less excised than in S. anæstheta. Length, about 430; culmen, 53; wing, 298; tail, about 190; depth of fork, 102; tarsus, 23; middle toe with claw, 28.

“Adult in winter.—Like the above, with white flecks on the lores and crown.

“Immature.—Brownish black above, darker on the upper wing-coverts; outer tail-feathers nearly as sooty black as the rest of the rectrices, except toward the tips; tarsi and toes reddish brown.

“Nestling and young.—The chick when about three days old is streaked with grayish brown and dull white on the upper surface, darkest on the forehead, and chiefly stone-white below; when half fledged, the feathers of the mantle are blackish, with broad white tips, which gradually wear down. When the bird is fully fledged these white tips are much narrower, the feathers of the upper parts are sooty brown, and the under parts are also somewhat paler brown, becoming lighter toward the vent. (In S. anæstheta the under parts are whitish). Bill and feet reddish brown.” (Saunders.)

83. STERNA SINENSIS Gmelin.
WHITE-SHAFTED TERN.

Luzon (Whitehead); Mindanao (Steere Exp.); Mindoro (Bourns & Worcester); Palawan (Whitehead). Chinese and Indian seas to Australia.

“Adult male in breeding plumage.—Lores black from base of bill to eye; forehead as far as a little beyond the top of eye white; crown and nape black; mandible pearl-gray; secondaries bordered with grayish white; shafts of primaries pure white in the outer, and pale gray in the upper ones; outer web of the outer primary and a broad line next the shaft on its inner web dark gray; on the succeeding primaries paler gray; upper portions and edges of inner webs white; rump pearl-gray; tail and under parts white. Bill gamboge-yellow, tipped with black; tarsi and feet orange-yellow. Length, 280 when the streamers are fully developed; culmen, 35; wing, 188; tail, 145; depth of fork, 86; tarsus, 16; middle toe with claw, 20.