1. (Science: zoology) Any one of several species of large old world ducks of the genus Tadorna and allied genera, especially the European and Asiatic species. (T. Cornuta, or tadorna), which somewhat resembles a goose in form and habit, but breeds in burrows.
The Australian sheldrake (Tadorna radja) has the head, neck, breast, flanks, and wing coverts white, the upper part of the back and a band on the breast deep chestnut, and the back and tail black. The chestnut sheldrake of australia (Casarca tadornoides) is varied with black and chestnut, and has a dark green head and neck. The ruddy sheldrake, or Braminy duck (C. Rutila), and the white-winged sheldrake (C. Leucoptera), are related Asiatic species.
2. Any one of the American mergansers.
Origin: Sheld _ drake.