128 AVES. 



their eye-brows project, which occasions the eye to appear sunk, and gives 

 to their physiognomy a character very different from that of the Vultures: 

 the greater number prey on living animals, but they differ in the coiirage 

 with which they pursue it. Their first plumage is often very differently 

 coloured from that of the adult, which is only assumed in their third or 

 fourth year, a circumstance which has occasioned a great multiplication of 

 species. The female is generally one-third larger than the male, which, 

 on this account, is styled a tarselov tercel. We should, first of all, subdivide 

 this genus into two great sections. 



NOBLE BIRDS OF PREY. 



Falcons, properly so called. 



The true Falcons constitute the first, and, in proportion to their size, are 

 the most courageous, a quality which is derived from the power of their 

 arms and M'ings; their beak, curved from its base, has a sharp tooth on each 

 side of its point, and the second quill of their wings is the longest, the first 

 nearly equalling it, which renders the whole wing longer and more pointed- 

 From this, also, result peculiar habits: the length of the quills of their wings 

 diminishes their vertical power, and compels them, in a calm state of the 

 atmosphere, to fly obliquely forwards, so that when they wish to rise 

 directly upwards, they are obliged to fly against the wind. 



F. communis, Gm. (The Common Falcon. ) As large as a Hen, and dis- 

 tinguished by a triangular, black moustache on the cheek, larger than that 

 of any other species of the genus; it varies as to colours accorc^g to its age. 



It is this celebrated species which has given its name to that kmd of hunt- 

 ing in which birds of prey are used. It inhabits the whole north of the 

 earth, and builds in the most elevated and inaccessible cliffs. 



HiEROFALCO, CuV. (1) 



The Gerfalcons have wing quills similar to those of the other Noble birds, 

 which they perfectly resemble in disposition; but their beak has only an 

 emargination like thatof the Ignoble ones. Only one species is well known. 



F. candicans. (The Gerfalcon.) One fourth larger than the Falcon, and 

 the most highly esteemed by falconers. It is chiefly obtained from the 

 north; its usual plumage is brown above, with an edging of paler points on 

 each feather, and transverse lines on the coverts and quills. 



The second section of the great genus Falco is that of the 



IGNOBLE BIRDS OF PREY. 



So called, because they cannot be easily employed in falconry; a tribe 

 much more numerous than that of the Nobles, and which it is also necessary 



(1) Hierax, Hiero-falco, Sacred Falcon, &c. names connected with the 

 superstitions of the Egyptians respecting certain birds of prey. Gerfalcon 

 is a corniption of Hierofalco- 



