Sheldrake, Or Shieldrake, the common name of the river ducks of the subfamily anatinoe and of the genera tadorna (Leach) and casarka (Bonap.). In tadorna the bill is shorter than the head, higher at the base than broad, with culmen concave in the middle, depressed, curved upward at the tip, which is suddenly hooked and has a strong narrow nail; lamellae slender and widely set; nostrils large, near the culmen; wings moderate, pointed, the second quill longest, and armed on the shoulder with a tubercle; tail moderate, nearly even; tarsi strong, shorter than the middle toe; toes short, fully webbed; hind toe elevated, slightly lobed; claws moderate and curved. They are widely distributed over the old world, on the seacoast as well as on rivers and lakes, migrating in winter from the north; they feed on marine plants and worms, crustaceans, and mollusks; the nest is made of grass lined with down, and is often placed in the deserted burrows of rabbits and other rodents; they lay 12 to 14 eggs. The common sheldrake (T. vulpanser, Flem.) is one of the handsomest of water fowl, the colors being brilliant and pure, and strongly contrasted.
In the male the bill is vermilion; the head and upper neck green bounded by a white collar, below which is another of rich chestnut covering the upper breast and back; rest of back, rump, and upper tail coverts white; scapulars nearly black, outer webs of long tertials chestnut, point of wing and its coverts white, primaries dark brown, and speculum green; tail white, tipped with black; abdomen rich dark brown; sides, vent, and under tail coverts white; the length is 24 to 26 in.; the female is smaller and not so bright, and the young are more brownish. The windpipe is about 10 in. long, having on each side at its lower portion a hollow, globular, bony protuberance, generally much larger on one side than the other. The note is a shrill whistle; the flesh is coarse, dark, and of unpleasant odor and flavor; the eggs are shining white, 2 3/4 by 2 in.; incubation lasts 30 days, both sexes sitting; they are easily domesticated, and are often raised by hens. Yarrell thinks the names are derived from their favorite shell food, and from their frequent use on heraldic shields; they are also called burrow ducks from their common places of breeding, also skeeling geese in Scotland, and sly geese (from their devices for leading intruders from their nests and young) in the Orkney islands.
Two other species are found in Australia. - In the genus casarka the bill is as long as the head, nearly straight, the width equal to the height at the base, the anterior half depressed, scarcely curved upward at tip, which has a strong and broad nail; wings moderate, the second quill the longest; tail short and rounded; tarsi robust, shorter than the middle toe; toes long, fully webbed; hind toe long, elevated, and lobed. The ruddy sheldrake (C. rutila, Bonap.) is about the same size as the last, with similar breeding habits; in the male the bill is lead-colored; the head, cheeks, and chin buff, becoming orange brown at the lower part of the neck all round, where there is a ring of black; the back, tertials, breast, and under parts like the head; wing coverts pale buff white; primaries and tail dark leaden gray, secondaries lighter, and speculum brilliant green; the female is rather smaller and lighter colored, with white on the throat and wings, but without the black collar. It is sometimes called collared duck, and ruddy goose; it is a native of eastern Europe and western Asia, coming as far west as England and south to Italy and Africa; it is fond of breeding in the holes of marmots in river banks, and the eggs are 8 to 10. Other species are found in Australia and New Zealand, and they all resemble geese in general form, and especially in the females having the plumage. colored nearly like the males. - In America the name of sheldrake is given to the red-breasted merganser, which resembles the European sheldrake only in the color of its breast. (See Merganser).
Common Sheldrake (Tadorna vulpanser).