Part 36

c1. Forehead black to base of culmen.

d1. Larger; tarsus yellow or red; bill red in summer. ... hirundo (p. 89) d2. Smaller; tarsus blackish, bill black at all seasons. ... longipennis (p. 89)

c2. Forehead white.

d1. Lores white. ... boreotis (p. 90) d2. Lores black.

e1. Wing, 265 mm.; mantle umber-brown. ... anæstheta (p. 91) e2. Wing, 300 mm.; mantle deep black. ... fuscata (p. 92)

b2. Smaller; wing less than 200 mm. ... sinensis (p. 92)

a2. Crown white. ... melanauchen (p. 93)

78. STERNA HIRUNDO Linnæus.

COMMON TERN.

Sterna hirundo Linnæus, Syst. Nat. ed. 10 (1758), 1, 137. Sterna fluviatilis Saunders, Cat. Birds Brit. Mus. (1896), 25, 54; Sharpe, Hand-List (1899), 1, 135; Oates, Cat. Birds' Eggs (1901), 1, 182; McGregor and Worcester, Hand-List (1906), 20.

Calayan (McGregor). Countries on both sides of Atlantic Ocean, Indian and African coasts in winter, Brazilian coasts in winter.

"Adult male in breeding plumage.--Forehead, upper lores, crown, and nape black; mantle rather dark pearl-gray; secondaries narrowly margined with white; outer primary with a black outer web, and a broad streak (10 mm.) of very dark gray next the white shaft on inner web, rest of inner web white, except toward tip, where it is dark ash-gray; inner primaries paler gray, with white 'wedges' and dark gray margins to inner webs; rump whitish; tail-feathers white, with gray outer webs, those of the streamers darkest; chin and cheeks white; breast and belly pale, vinaceous-gray; under wing- and under tail-coverts white. Bill coral-red, the extreme tip horn-color; iris dark brown; tarsi and toes coral-red. Length, 362; culmen, 43; wing, 267; tail, 165; depth of fork, 82; tarsus, 22; middle toe with claw, 24.

"Female.--Similar to the male.

"Adult in winter plumage.--Like the above, but forehead and crown streaked and mottled with white; colors of bill and feet much duller from September onwards, under parts paler.

"Immature.--Like the above, but the forehead white; a dark gray band along upper wing-coverts; under parts distinctly white.

"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.)

80. STERNA BOREOTIS (Bangs).

NORTHERN BERGIUS TERN.

Sterna bergii Saunders, Cat. Birds Brit. Mus. (1896), 25, 89 (part); Sharpe, Hand-List (1899), 1, 136 (part). Sterna bergii boreotis Bangs, Bull. Mus. Comp. Zool. (1901), 36, 256. Sterna boreotis McGregor and Worcester, Hand-List (1906), 20.