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280 ANATIDH, SWANS. 
passing notice. They are salacious to a degree remarkable even in the hot-blooded, 
passionate class of birds; a circumstance rendering the production of hybrids 
frequent, and favoring the study of this subject. If we recall the peculiar actions 
of geese nipping herbage, and of ducks ‘‘dabbling” in the water, and know that 
some species, as the mergansers, pursue fish and other live prey under water, we 
have the principal modes of feeding. Nidification is usually on the ground; 
sometimes in a hollow tree; the nest is often warmly lined with live feathers; 
the eggs are usually of some plain pale color, as greenish or creamy; the clutch 
varies in number, commonly ranging from half a dozen to a dozen and a half. 
The young are clothed with stiffish down, and swim at once. Among the ducks 
and mergansers, marked sexual diversity in color is the rule; the reverse is the 
case with swans and geese. A noteworthy coloration of many species, especially 
of ducks, is the speculum; a brightly colored, generally iridescent, area on the 
secondary quills. Most of the species are migratory, particularly those of the 
northern hemisphere; the flight is performed in bands, that seem to preserve 
discipline as well as companionship; and with such regularity, that no birds are 
better entitled to the claim of weather-prophets. 
There are upward of 175 species of this family, inhabiting all parts of the world. 
They differ a good deal in minor details, and represent a number of peculiar genera 
aside from the ordinary types, though none are so aberrant as to endanger the 
integrity of the group. It is difficult to establish divisions higher than generic, 
because the swans, geese and ducks, if not also the mergansers, are closely united 
by intermediate genera. But the five groups presented as subfamilies in the 
following pages, and representing the whole of the family, may be conveniently 
recognized, and are readily distinguished, so far as our species are concerned, 
by the characters assigned. 
Subfamily CYGNIN4!. Swans. 
A strip of bare skin between the eye and bill; tarsi reticulate. In the swans, the 
neck is of extreme length and flexibility ; the movements and attitudes on the water 
are proverbially elegant and graceful. The bill equals or exceeds the head in length ; 
it is high and compressed at base (where sometimes tuberculate), flatter and _ 
widened at the end; the nostrils are median. Some of the inner remiges are 
usually enlarged, and when elevated in a peculiar position of the wing, they act as 
sails to help the course of the bird over the water. The legs are placed rather far 
back for this family, so that the gait is awkward and constrained. The tail is short, 
of 20 or more feathers. Although the voice is sonorous at times, an habitual 
reticence of swans contrasts strongly with the noisy gabbling of geese and ducks ; 
it is hardly necessary to add, that their fancied musical ability, either in health or 
at the approach of death, is not confirmed by examination of their vocal apparatus ; 
this is in many cases convoluted as already described, but there are no syringeal 
muscles nor other apparatus for modulating the voice. There are eight or ten 
species, of various countries, among them the celebrated black swan of Australia, 
Chenopsis atratus, the black-necked swan of South America, Cygnus nigricollis ; 
and the Coscoroba anatoides of the same country, a species with feathered lores; in 
none of these does the trachea enter the breast-bone. Our two species belong to 
the subgenus Olor, distinguished from Cygnus proper by absence of a tubercle 
at the base of the bill. The sexes are alike throughout the group. 
