SLATE-COLORED HAWK. 
63 
in its green or first year's dress. In tlie 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. 
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 suspi- 
cion that this might be one of those with Avhich 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 Avhich 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, barred with dusky ; scapulars spotted with 
white and Ijrown, wliich 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 Avhite ; 
chin white mixed Avitli fine black hairs ; breast and belly beautifully 
variegated with ferruginous and transverse spots of white ; femorals the 
same ; vent pure wliite, 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 Avas found to be a male. In the month of Fe1)ruary, I shot another 
individual of this species, near Hampton in Virginia, Avhich agreed 
almost exactly Avith the present. 
