The plumage of the bird is soft, dense, and glossy; the feathers of the head and neck blended and velvety; the wings short, narrow, and pointed; the upper mandible orange red, the protuberance on each side yellowish grey; at the base is a large square patch of black, margined with orange red, with a patch of greyish white in front.
Intimately allied to the Ducks in many respects, and to the Divers and Cormorants in others, are the Mergansers, a very distinct family, characterised by a large, elongated, and depressed body; long and slender neck; oblong, compressed head, narrowing anteriorly; bill straight, narrow, and slender, sub-cylindrical outwards, wide at the base, and abruptly hooked at the tip; margins of both mandibles serrated; the teeth directed backwards.
The Goosander.
English Synonyms.—Goosander: Montagu, Selby, Jenyns. Dun Diver: Montagu. Buff-breasted Goosander: McGillivray. Greater Goosander, Saw-bill, Jacksaw.
Latin Synonyms.—Mergus merganser: Linn., Latham, Temminck, Selby, Jenyns. Mergus castor: Linn., Latham. Merganser castor: Bonaparte, McGillivray.
French Synonyms.—Bieune of the old French. Grand Harle: Temminck.
The Merganser (Mergus, from mergere, to submerge) is sometimes separated from the Ducks. Prince Charles Bonaparte includes in it two sub-genera, the Smew (Mergus) and the Merganser of Leach. The Merganser is distinguished by its slender and almost cylindrical bill, armed on the edges with points turning backwards, somewhat resembling the teeth of a saw; yet, in its general appearance, plumage, and habits, this bird bears much resemblance to the Ducks.
The Mergansers very rarely come on land; they are exclusively aquatic, and frequent rivers, lakes, and pools, preferring them to estuaries; but they may be seen in summer fishing in the sea-lochs of Scotland. The Latins gave them the name of Mergus in consequence of their habit of swimming with the body submerged—the head only appearing above the surface of the water.
These birds feed on fish, of which they destroy an immense number. They also commit serious depredations on the spawning beds. They are able to accumulate a large quantity of air in the trachea, and can therefore remain some time under water without breathing. They take advantage of this for diving to the bottom to seek their prey, and they will often travel to a considerable distance before they appear again on the surface. The activity they display in pursuit of their prey is very great; for, in order to accelerate their speed in swimming, they make use of their wings as well as of their feet. The Merganser is in the habit of swallowing fish head first; consequently, it often happens that the remainder of the body of their prey is too bulky to be easily gorged; they are, however, very far from wishing to get rid of this temporary inconvenience, but wait till it becomes gradually absorbed. Sometimes the digestion of the fish's head has already commenced in the bird's stomach whilst the tail is still projecting from its bill.