SLATE-COLOURED HAWK. 2 \J~ 



irregular and swiftly ; preys on lizards, mice, and small birds, 

 and is an active and daring little hunter. It is drawn of full 

 size, from a very beautiful specimen shot in the neighbour- 

 hood of Philadelphia. The bird within his grasp is the 

 Tanagra rubra, or black-winged red bird, in its green or 

 first year's dress. In the spring of the succeeding year the 

 green and yellow plumage of this bird becomes of a most 

 splendid scarlet, and the wings and tail deepen into a glossy 

 black. For a particular account of this tanager, see Vol. I. 

 p. 192, of the present work. 



The great difficulty of accurately discriminating between 

 different species of the hawk tribe, on account of the various 

 appearances they assume at different periods of their long 

 lives, at first excited a suspicion that this might be one of 

 those with which I was already acquainted, in a different 

 dress, namely, the sharp-shinned hawk just described; for 

 such are the changes of colour to which many individuals of 

 this genus are subject, that unless the naturalist has recourse 

 to those parts that are subject to little or no alteration in the 

 full-grown bird, viz., the particular conformation of the legs, 

 nostril, tail, and the relative length of the latter to that of the 

 wings, also the peculiar character of the countenance, he will 

 frequently be deceived. By comparing these, the same species 

 may often be detected under a very different garb. Were all 

 these changes accurately known, there is no doubt but the 

 number of species of this tribe at present enumerated would 

 be greatly diminished, the same bird having been described 

 by certain writers three, four, and even five different times, 

 as so many distinct species. Testing, however, the present 

 hawk by the rules above mentioned, I have no hesitation in 

 considering it as a species different from any hitherto described, 

 and I have classed it accordingly. 



The slate-coloured hawk is eleven inches long, and twenty- 

 one inches in extent ; bill, blue black ; cere and sides of the 

 mouth, dull green ; eyelid, yellow ; eye, deep sunk under the 

 projecting eyebrow, and of a fiery orange colour ; upper parts 



