SLATE-COLORED HAWK. 63 



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 (1 e wings and tail deepen into a glossy black. 



The great difficulty of accurately, discriminating between diiferent 

 species of the Hawk tribe, on account of the various appearances they 

 assume at different periods of their long lives, at first excited a suspi- 

 cion that this might be one of those with which I was already acquainted, 

 in a different dress, namely, the Sharp-shinned Hawk, figured in Plate 

 XLV. of this work ; for such are the changes of color to which many 

 individuals of this genus are subject, that unless the naturalist has re- 

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

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

 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 dif- 

 ferent from any hitherto described ; and I have classed it accordingly. 



The Slate-colored Hawk is eleven inches long ; and twenty-one inches 

 in extent ; bill blue black ; cere .and sides of the mouth dull green ; eye- 

 lid yellow ; eye deep sunk under the projecting eyebrow, and of a fiery 

 orange color ; upper parts of a fine slate ; primaries brown black, and, 

 as well as the secondaries, baxTed with dusky ; scapulars spotted with 

 white and brown, which is not seen unless the plumage be separated by 

 the hand ; all the feathers above are shafted with black ; tail very 

 slightly forked, of an ash color, faintly tinged with brown, crossed with 

 four broad bands of black, and tipped with white ; tail three inches 

 longer than the wings ; over the eye extends a streak of dull white ; 

 chin white mixed with fine black hairs ; breast and .belly beautifully 

 variegated with ferruginous and transverse spots of white ; femorals the 

 same ; vent pure white, legs long, very slender, and of a rich orange 

 yellow ; claws black, large, and remarkably sharp ; lining of the wing 

 thickly marked with heart-shaped spots of black. This bird on dissec- 

 tion was found to be a male. In the month of February, I shot another 

 individual of this species, near Hampton in Virginia, which agreed 

 almost exactly with the present. 



