STERNA, a genus of birds, of the order of anseres. There are seven species, three of which are British, viz. 1. The hirundo, or great tern, weighs four ounces one-quarter: the length is fourteen inches; the breadth thirty: the bill and feet are of a fine crimson; the former tipped with black, straight, slender, and sharp-pointed: the crown, and hind part of the head, black: the throat, and whole underside of the body, white: the upper part, and the coverts of the wings, a fine pale grey: the tail consists of twelve feathers; the exterior edges of the three outmost are grey, the rest white: the exterior, on each side, is two inches longer than the others: in flying, the bird frequently closes them together, so as to make them appear one slender feather. These birds frequent the sea-shores, banks of lakes and rivers: they feed on small fish, and water-insects; hovering over the water, and suddenly darting into it, catch up their prey. They breed among small tufts of rushes; and lay three or four eggs, of a dull olive colour, spotted with black. All the birds of this genus are very clamorous.
2. The lesser tern, called by Linnaeus larus minuta, weighs only two ounces five grains; length eight inches and a half; the breadth nineteen and a half. The bill is yellow, tipped with black: the forehead and cheeks white: from the eyes to the bill is a black line: the top of the head and hind part black: the breast, and under side of the body clothed with feathers so closely set together, and of such an exquisite rich gloss, and so fine a white, that
that no fatin can be compared to it: the back and wings of a pale grey: the tail short, less forked than that of the former, and white: the legs yellow: the irides dusky.—These two species are very delicate, and seem unable to bear the inclemency of the weather on our shores during winter; for we observe they quit their breeding places at the approach of it, and do not return till spring. The manners, haunts and food of this are the same with those of the former; but these are far less numerous.
3. The sillsips, or black tern, is of a middle size between the first and second species. The usual length is ten inches; the breadth twenty-four; the weight two ounces and a half. The head, neck, breast, and belly, as far as the vent, are black; beyond is white: the male has a white spot under its chin: the back and wings are of a deep ash-colour: the tail is short and forked; the exterior feather on each side is white; the others ash-coloured: the legs and feet of a dusky red. Mr Ray calls this a cloven-footed gull; as the webs are depressed in the middle, and form a crescent. These birds frequent fresh waters; breed on their banks, and lay three small eggs of a deep olive-colour, much spotted with black. They are found during spring and summer in vast numbers in the Fens of Lincolnshire; make an incessant noise, and feed as well on flies as water-insects and small fish. Birds of this species are seen very remote from land. Kalm saw flocks of hundreds in the Atlantic Ocean, midway between England and America; and a later voyager saw one 240 leagues from the Lizard, in the same ocean.