92 FALCONID.E. 



claws, winch arc all nearly of equal length, are slender, and 

 but little arched ; the middle one is dilated on the inner 

 edge, and sharp ; the outer and middle toes united by a 

 membrane. The body is long and slender. The wings 

 are long, measuring from carpus to tip seventeen inches two ' 

 lines ; the first and second quill-feathers are short, the third 

 the longest in the winsf. The tail feathers measure ten 

 inches. The lower part of the face is surrounded by a ruff 

 of stiff feathers, and capable of erection at the will of the 

 the bird : the rest of the plumage is soft and rather loose : 

 the wings, when closed, reach nearly to the end of the tail. 

 These measurements were taken from a specimen in the 

 Zoological Museum, the same which forms the subject of 

 the plate. According to Montagu, the entire length of 

 one measured by him was twenty-three inches, and weighed 

 twenty-eight and a half ounces : the male is rather less in 

 weight and dimensions. 



The bill is dusky, the cere, iris, and legs yellow in the 

 adult birds ; in younger subjects the cere and legs are paler 

 yellow, inclining to greenish, the iris dark brown. 



This bird, in consequence of the great difference in 

 plumage between the young and old, and the time that 

 elapses before it arrives at maturity, was formerly multiplied 

 into several different species. Its various changes, which 

 chiefly depend upon age, are however now well understood, 

 and to the elucidation of them we are greatly indebted 

 to Montagu and Selby, Temminck, and other continental 

 authors. 



The young birds of the first year have the head and throat 

 yellowish white, tinged with rust colour, the rest of the plum- 

 age, including the yet unmarked disk, chocolate brown, re- 

 flecting tints of violet upon the back : the under surface of 

 the wings and tail are pearly ash grey. In this state of 



