ANATIDuE — CYGNIN^ : SWAN^. 
681 
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 ''dab- 
bling " 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, drab, 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 diver- 
sity in color is the rule ; the reverse is the case with swans and geese. A noteworthy color- 
ation 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, thougli 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, \{ 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 con- 
veniently recognized, and are readily distinguished, so far as our species are concerned, by the 
characters assigned. The genera will be found analyzed under heads of their respective 
subfamilies. 
Analysis of Subfamilies. 
Cygnin^. Swans. Lores partly naked. Tarsi reticulate. Hallux simple. Sexes alike. 
Anserine. Geese. Lores feathered. Tarsi reticulate. Hallux simple. Sexes alike. 
AuATiNJE. River Bucks. Lores feathered. Tarsi scutellate in front. Hallux simple. Bill flattened. Sexes 
unlike. 
FuLiGULiN.^:. Sea Ducks. Lores feathered. Tarsi scutellate in front. Hallux lobate. Bill flattened. 
Sexes unlike. 
Merging. Mergansers. Lores feathered. Tarsi scutellate in front. Hallux lobate. Bill cylindric. Sexes 
unlike. 
65. Subfamily CYCNIN/E: Swans. 
A strip of hare skin between the eye and hill ; tarsi 
reticulate, and shorter than middle toe and claiu ; 
hind toe simple, or with very slight lobe. In the 
Swans, the neck is of extreme length and flexibility, 
exceeding the trunk, with up to 22 or 26 vertebrae ; 
the movements and attitudes on the "water are pro- 
verbially elegant and graceful. The bill equals or 
exceeds the head in length ; it is high and com- 
pressed at base (where sometimes tuberculate) , flat- 
ter and widened at the end ; the nostrils are median. 
The lores are naked in the adults, though usually 
feathered in the young. Some of the inner remiges 
are usually enlarged, and when elevated in a pecu- 
FiG. 471. — Mute Swan, Cygnus olor. (From liar position of the wing, they act as sails to help the 
^'^""•^ course of the bird over the water. The reticulate 
tarsi are shorter than the middle toe and claw. The hallux is scarcely or not lobate. The legs 
are placed rather far back for this family, so that the gait is awkward and constrained. The 
