A Manual of Philippine Birds

by Richard C. McGregor

Genera.

• a¹. Tail more or less forked.
  • b¹. Tail but little more than one-third of wing, its outer feathers broad and rounded. Hydrochelidon (p. [86])
  • b². Tail much more than one-third of wing, its outer feathers narrow and pointed. Sterna (p. [88])
• a². Tail graduated; plumage sooty brown. Anous (p. [94])

Genus HYDROCHELIDON Boie, 1822.

Bill short and slender; legs and feet small; webs between the toes deeply emarginate; wings long, when closed, exceeding the tail; tail short, nearly square.

Species.

• a¹. Black or dark gray below (adults in summer).
  • b¹. Upper tail-coverts and tail white; under wing-coverts black. leucoptera (p. [86])
  • b². Upper tail-coverts and tail gray; under wing-coverts white. hybrida (p. [87])
• a². White below (adults in winter and young).
  • b¹. Tail white. leucoptera (p. [86])
  • b². Tail gray.
    • c¹. Rump gray like back. hybrida (p. [87])
    • c². Rump white (young). leucoptera (p. [86])

76. HYDROCHELIDON LEUCOPTERA (Meisner and Schinz.)

WHITE-WINGED BLACK TERN.

• Sterna leucoptera Meisner and Schinz, Vog. Schweiz (1815), 264.
• Hydrochelidon leucoptera Saunders, Cat. Birds Brit. Mus. (1896), 25, 6; Sharpe, Hand-List (1899), 1, 133; Oates, Cat. Birds’ Eggs (1901), 1, 174; McGregor and Worcester, Hand-List (1906), 20.

Mindanao (Steere Exp., Bourns & Worcester). Central and southern Europe to central Asia and China; Australia, New Zealand, Africa in winter.