16 INTRODUCTION. 



In the Accipitres, represented by the Eagles and 

 Falcons, the wings are long and powerful, and their 

 food consisting mostly of the flesh of small animals, 

 they are not only assisted in their pursuit of them 

 by a rapid and vigorous flight, but the form of the 

 feet and claws is such as to enable them to seize and 

 secure their prey, while the hooked beak is well 

 suited to the purpose of tearing it in pieces. 



The Insessores embraces a great variety of birds 

 exhibiting a corresponding variety of form. A large 

 majority of them feed upon insects and their larvae 

 or eggs ; and while in all, the feet are well adapted 

 for perching, the bill and wings will be found to vary 

 much according to the habits of the bird. The 

 Swallows, Fly-catchers, Tyrants, etc., pursue their 

 food upon the wing ; they have therefore great powers 

 of flight, the mouth is wide, the bill broad at the 

 base, and sometimes armed at the extremity with a 

 slight hook. The Warblers, Thrushes, Wrens, and 

 many others, seek their food among the branches and 

 leaves of the trees, feeding mostly upon the worms, 



and Oscines. Of the ten families belonging to the first (the 

 inferior), five are represented in the United States; of the 

 second, which exhibits the higher organization, the whole 

 ten families exist in our country. 



This system was first published at Upsal in 1860, by 

 Wilhelm Lilljeborg. 



In the present book, the liberty has been taken of alter- 

 ing the author's arrangement as far as possible, and the 

 classification proposed by Lilljeborg has been substituted. 



E. D. C. 



