Song Birds and Water Fowl 
and subsist largely upon animal food which 
they find in the water. The nature of their 
diet makes their flesh rank and usually unpal- 
atable, although the ‘‘ canvas-back’’ is a not- 
able exception. These rarely breed as far south 
as the United States, but commonly far north, 
one of the largest and handsomest, the king 
eider, being circumpolar. Sea ducks differ 
from river ducks in having larger feet and 
broader webs, enabling them to swim and 
dive more easily. I will mention one curious 
and significant distinction between the two 
groups, although it touches upon the anatomi- 
cal side of the subject. In all sea ducks the 
hind toe is bordered by a narrow band or lobe, 
which is never the case in river ducks. ‘This 
increases the area of the webbed foot, and the 
relation of this fact to the different degrees of 
propulsive power possessed by the two groups, 
which in turn so largely determines their habi- 
tat and diet, and thus their serviceableness to 
man, justifies an allusion to what might other- 
wise be called a dry, scientific fact. The field 
ornithologist ignores nothing in the physique 
of a bird that has an evident relation to the 
special habits of the species; but the intricate 
details of an insignificant bone in the body that 
86 
