90 INTRODUCTION. 



a., and digital or primary, 35, and Fig. 29, b. Those on 

 the first finger, 35, are named akilar. The series of large 

 feathers immediately covering the quills is composed of the 

 larger coverts, which are also named humeral, cubital or secon- 

 dary, 36, and digital or primary, 37. The other feathers of 

 the wing are named the smaller wing-coverts. The lower sur- 

 face of the wing is similarly feathered. 



In the posterior extremities, or legs, are distinguished the 

 femoral region or thigh, generally concealed ; the leg properly 

 so called, or the tibia, 38, generally feathered, sometimes bare 

 for a gi'eater or less extent above the ancle joint, which is gene- 

 rally mistaken for the knee ; the tarsus, 39, almost always bare, 

 and covered with scales or plates, of various forms, and vari- 

 ously disposed. 



Lastly, we have the toes, 40, which vary in number, al- 

 though there are ncA^er more than four, unless the spur be con- 

 sidered as a toe, nor fewer than three ; for the Ostrich, which 

 was formerly held to have only tw^o, has lately been shewn by 

 Dr. Riley to have moreover a rudimentary inner toe. They 

 are covered above w^ith scales of large size, laterally with 

 smaller, beneath with papillae, and have their extremities 

 sheathed with horny claws, varying much in length and form 

 in the different species, and in the present bird, the Kestrel, 

 long, curved, and tapering to a fine point. 



These introductory observations will sufiice to enable the 

 reader to follow me in my descriptions, which comprehend, 

 besides the details of the exterior, several particulars respecting 

 the internal structure of the different species. To acquire a 

 satisfactory knowledge of any bird, one must, in the first place, 

 obtain a general idea of its external appearance, so as not only 

 to be able to distinguish it at sight, but also to knov>^ in what 

 respects it resembles others, or differs from them. Then he 

 ought to examine its interior, and more especially its digestive 

 organs, which indicate the nature of its food, the latter neces- 

 sarily determining its haunts. He now seeks it there, and 

 observes its mode of walking and flying, its favourite places of 

 resort, and its ^'arious actions, listens to its notes, follows it to 



