The members of this large assemblage are, with possibly slight exception, so typically ” Duck-like ” in appearance that there can usually be no difficulty in their recognition. They are all aquatic or semi-aquatic in their habits, and, with a single exception, the Pied Goose of Australia, all have webbed feet. With limited exceptions, such as the Steamer Duck of South America and a few others, all the members of the group are good, not to say strong, flyers. The bill is generally broad and flattened, with the edges laminated, although in several groups it becomes narrower and more or less tapering to a point ; in all, however, the upper mandible terminates in a nail. The legs are short and usually placed far back on the body, an adaptation which permits rapid movement through the water. The plumage is close and compact, and there are relatively few bare spaces. It is perhaps unnecessary to go into the anatomical characters, at least beyond those set forth on the preceding pages, as certain of the more important details of structure will be taken up under the various groups. It may be stated, however, that when the moult takes place the feathers of the wing are generally shed at once, thus incapacitating them for flight for a short period.
The Anseres number about seventy living genera and two hundred and ten species, and are cosmopolitan in distribution, though most abundant in the more northern portions of the Western Hemisphere. Several genera and a large number of fossil forms have been described, yet none of them is of very great antiquity. The members of this group are all more or less sociable, and may often be seen feeding in flocks, and during the breeding season often nest in proximity, though not in such colonies as characterize, for example, the group last considered. Most of them are strongly migratory and while on these journeys to and from the summer home often fly in single file or V-shaped formation, under the direction of an apparently competent and trusted leader. The nests are usually placed on the ground, occasionally in hollow trees, and the complement of eggs is usually large, ranging from some four or five to a dozen or more. These have hard, generally smooth shells and are even or uniform in coloration.