Bill black: legs reddish brown: membranes of the toes deeply emar-ginated: tarsus seven lines and a half: tail not much forked, shorter than the wings.
S. nigra, Temm. Man. d'Orn. torn. ii. p. 749. Black Tern, Mont. Orn. Diet, & Supp. Bew. Brit. Birds, vol. ii. p. 195. Selb. Must. vol. ii. p. 477. pl. 91.
Entire length ten inches three lines: length of the bill (from the forehead) one inch two lines, (from the gape) one inch seven lines and a half; of the tarsus seven lines and a half; of the tail three inches three lines; from the carpus to the end of the wing eight inches eight lines: breadth, wings extended, twenty-three inches six lines.
(Summer plumage). Head and neck deep black: breast and abdomen dark ash-colour: all the upper parts, including the rump and tail, deep bluish gray: vent and under tail-coverts pure white: wings, when closed, extending one inch seven lines beyond the tail: bill black: irides brown: legs purplish brown. (Winter plumage). Forehead, space between the bill and the eyes, throat and all the fore part of the neck, white: the rest as in summer. In the intermediate seasons, these parts are often found mottled with black upon a white ground. (Young of the year). " Forehead, space between the eye and the bill, sides and front of the neck, as well as all the under parts, pure white: on the sides of the breast a large patch of dusky ash: before the eyes a crescent-shaped spot of the same colour: crown, occiput and nape, black: back and scapulars brown, the feathers edged and tipped with reddish white: wings, rump and tail, ash-colour; the wing-coverts tipped with reddish white: bill brown at the base: irides brown: legs livid brown." Temm. (Egg). Dark olive-brown, blotched and spotted with black, principally at the larger end: long. diam. one inch five lines; trans, diam. one inch.
A more inland species than any of the foregoing. Found principally in marshes, and on the banks of rivers and lakes. First seen towards the latter end of April: departs in October. Common in Romney Marsh in Kent, and also in the fens of Cambridgeshire and Lincolnshire, where they breed. Eggs two to four in number, deposited on the bare grass in swampy and sedgy spots. Young hatched in the beginning of July. Food, worms and aquatic insects. Obs. The S. ncsvia of Gmelin is the young of this species.