1500. Sterna cantiaca.
The Sandwich Tern.
Sterna cantiaca, Gm. Syst. Nat. i, p. 606 (1788); Hume, S. F. i, p. 285 ; id. Cat. no. 990 bis : Blanford, Eastern Persia, ii, p. 294; Barnes, Birds Bom. p. 432 ; id. Jour. Bom. N. H. Soc. vi, p. 300; Saunders, Cat. B. M. xxv, p. 75.
Coloration. In breeding plumage the forehead, upper lores, crown, nape, and sides of head as far down as the lower edge of the orbits are black; back and wings pearl-grey; lower lores, cheeks, a collar round neck, all the lower parts, upper and lower tail-coverts, and tail white ; inner webs of primaries dark grey near the shafts, white inside, the inner white border extending to the tip of each feather, outer web of 1st primary blackish near base. In fresh plumage there is a slight and evanescent pink tinge to the underparts. The black head is only assumed from April till about June.
In non-breeding plumage the forehead and crown are white with black streaks, which are confluent on the nape and before and behind the eye. Immature birds resemble adults in winter plumage, but have a dark band on the smaller wing-coverts, and brown submarginal concentric bars on the tertiaries and tail; the primaries are dark grey, with sharply contrasting white inner borders. Still younger birds have most of the upper parts marked with concentric brown bands, and the crown-feathers blackish with white edges.
Bill black, with the tips of both mandibles pale horny yellow ; irides brown ; legs and feet black (Hume).
Length 17; tail 6, depth of fork 3; wing 12; tarsus 1.1 ; bill from gape 2.8. Females are a little smaller than males.
Distribution. Coasts of North Atlantic Ocean, Mediterranean, Black Sea, and Caspian in summer; in winter, African coasts as far as the Cape and Natal, Bed Sea, Persian Gulf, and Baluchistan. This bird is a winter visitor to the coast of Makran and Sind.
Habits, &c. This is a Sea-Tern often seen at sea several miles from the shore, and but rarely straying inland, though it has been found in Europe breeding on lakes near the coast.