10 INTRODUCTION'. 



then seen in the same humble and obhvious dress. When 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 ; 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.. Tlieir 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 tliem, 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 veniriculus, aflfords 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 



