468 SLATE-COLORED HAWK. 
Red-Bird, in its green or first year’s dress. In the spring of the suc- 
ceeding 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 page 125 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 suspi- 
cion that this might be one of those with which I was already ac- 
quainted, in a different dress, namely, the Sharp-shinned Hawk, just de- 
scribed ; for such are the changes of color 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-colored 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 color; upper parts of a fine slate; primaries, 
brown black, and, as well as the secondaries, barred with dusky ; scap- 
ulars, 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 tipt 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 dissection, was found to be amale. Inthe month 
of February, I shot another individual of this species, near Hampton, 
in Virginia, which agreed almost exactly with the present. 
