This wild but valuable species is of a size between the goose and the domestic duck, and appears to be one of the graduated links of the chain which connects the two kinds. The full-grown old males generally measure about two feet two inches in length, and two feet eight in breadth, and weigh from six to above seven pounds. The head is large; the middle of the neck small, with the lower part of it spread out very broad, so as to form a hollow between the shoulders, which while the bird is sitting at ease, seems as if fitted to receive its reclining head. The bill is of a dirty yellowish horn colour, darkish in the middle, and measures, from the tip to the corners of the mouth, two inches and a half: the upper mandible is forked in a singular manner towards each eye, and is covered with white feathers on the sides, as far forward as the nostrils. The upper part of the head is of a soft velvet black, divided behind by a dull white stroke pointing downwards: the feathers from the nape of the neck to the throat, are long, or puffed out, overhanging the upper part of the neck, and look as if they had been clipped off at the lower ends; they have the appearance of pale pea-green velvet shag, with a white line dropping downward from the auriculars on each side. The cheeks, chin, upper part of the neck, back, and lesser wing coverts, are white; the scapulars, and secondary quills, next the body, dirty white: bastard wings, and primary quills, brown; the secondaries and greater coverts are the same, but much darker: the lower broad part of the neck, on the front, to the breast, is of a buff colour; but in some specimens tinged with rusty red: the breast, belly, vent, rump, and tail coverts, are of a deep sooty black: tail feathers hoary brown: legs short and yellow: webs and nails dusky. The female is nearly of the same shape, though less than the male, weighing only between five and six pounds; but her plumage is quite different, the ground colour being of a reddish brown, prettily crossed with waved black lines: and in some specimens the neck, breast, and belly, are tinged with ash: the wings are crossed with two bars of white: quills dark: the neck is marked with longitudinal dusky streaks, and the belly is deep brown, spotted obscurely with black. The eider duck lays from three to five large, smooth, pale olive-coloured eggs; these she deposits and conceals in a nest, or bed, made of a great quantity of the soft, warm elastic down, plucked from her own breast, and sometimes from that of her mate. The groundwork or foundation of the nest is formed of bent grass, sea weeds, or such like coarse materials, and it is placed in as sheltered a spot as the bleak and solitary place can afford.