10 
INTRODUCTION.- 
then seen in the same humble and oblivious dress. AYhen they 
arrive again amongst us in the spring, the males in flocks, often 
by themselves, are clad anew in their nuptial livery ; and with 
vigorous songs, after the cheerless silence in which they have passed 
the winter, they now seek out their mates, and warmly contest the 
right to their exclusive favor. 
With regard to food, birds have a more ample latitude than quad- 
rupeds ; flesh, fish, amphibia, reptiles,- insects, fruits, grain, seeds, 
roots, herbs 5 in a word, whatever lives or vegetates. Nor are they very 
select in their choice, but often catch indifferently at what they can 
most easily obtain. Their sense of taste appears indeed much less 
acute than in quadrupeds ; for, if we except such as are carnivorous, 
their tongue and palate are, in general, hard, and almost cartilagin- 
ous. Sight and scent can alone direct them, though they possess 
the latter in an inferior degree. The greater number swallow with- 
out tasting; and mastication, which constitutes the chief pleasure in 
eating, is entirely wanting to them. As their horny jaws are unpro- 
vided with teeth, the food undergoes no preparation in the mouth, 
but is swallowed in unbruised and untasted morsels. Yet there is 
reason to believe, that the first action of the stomach, or its pre- 
paratory venlriculus , affords in some degree the ruminating gratifica- 
tion of taste, as after swallowing food, in some insectivorous and 
carnivorous birds, the motion of the mandibles, exactly like that of 
ordinary tasting, can hardly be conceived to exist without conveying 
some degree of gratifying sensation. 
The clothing of birds varies with the habits and climates they inhabit. 
The aquatic tribes, and those which live in northern regions, are 
provided with an abundance of plumage and fine down ; from which 
circumstance often we may form a correct judgment of their natal 
regions. In all climates, aquatic birds are almost equally feathered, 
and are provided with posterior glands containing an oily substance 
for anointing their feathers, which, aided by their thickness, pre- 
vents the admission of moisture to their bodies. These glands are 
less conspicuous in land-birds, unless, like the fishing Eagles, their 
habits be to plunge in the water in pursuit of their prey. 
The general structure of feathers seems purposely adapted both 
for warmth of clothing and security of flight. In the wings of all 
birds which fly, the webs composing the vanes, or plumy sides of 
the feather, mutually interlock by means of regular rows of slender 
hair-like teeth, so that the feather, except at and towards its base, 
serves as a complete and close screen from the weather on the one 
