72 
BLACK-SHOULDERED HAWK. 
from the rest in having the eyes dull yellowish-red ; the tail-feathers had all 
been ash-grey, all the primaries were edged with white, and many of the 
secondaries were still of a light brownish-grey ; the black spots under the 
wings were smaller than usual ; the abdomen was also tinged with brownish- 
grey. I am therefore of opinion, that these birds undergo as many changes 
of plumage as the Mississippi Kite. 
Black-winged Hawk, j Valeo melanopterus, Bonap. Amer. Orn., vol. ii. 
Falco melanopterus, Bonap. Syn., p. 31. Falco dispar , App. p. 435. 
Black-shouldered Hawk, Falco dispar , Aud. Amer. Orn., vol. iv. p. 397. 
Adult Male. 
Wings very long and pointed, the second quill longest, the third nearly as 
long, the first longer than the fourth ; the first, second, and third with the 
outer web attenuated toward the end ; the first and second with the inner web 
sinuated ; secondaries very broad, rounded, the inner web exceeding the 
outer. Tail of twelve feathers, of moderate breadth, long, emarginate and 
rounded, the middle and lateral feathers being about equal, and eight-twelfths 
of an inch-shorter than the second feather from the. side. 
Bill black ; the cere and soft basal margins yellow. Iris bright red. Tarsi 
and toes yellow, of a darker tint than the cere ; claws black. All the lower 
parts are pure white, with the exception of a patch on five or six of the 
larger wing-coverts; the forehead is also white, as are the cheeks ; the super- 
ciliary bristles black, the w T hite of the head gradually blends into the general 
colour of the upper parts, which is ash-grey ; the smaller wing-coverts bluish- 
black ; the shafts of the quills brownish-black ; all the feathers of the tail, 
excepting the two middle, white ; the shafts of the two middle feathers 
blackish-brown, of the rest white towards the end, the whole of that of the 
outer pure white. 
Length to end of tail 16 inches, to end of claws 12£, to end of wings 14£ ; 
extent of wings 40 ; wing from flexure 13 ; tall 7j-f ; bill along the ridge ; 
along the edge of lower mandible 1 t 5 j ; tarsus 1 T \ ; first toe - r 7 j, its claw I ; 
second toe V 0 ^, its claw ; third toe J, its claw fourth toe {%, its claw T ® 3 . 
Weight 14 oz. 
Adult Female. 
The female is rather larger than the male, but in other respects similar. 
Length to end of tail 161 inches, to end of wings 15£, to end of claws 
12f ; extent of wings 41£ ; tail 8 ; wing from flexure 13£ ; bill along the ridge 
1 b, along the edge of lower mandible Is ; tarsus 1§ ; hind toe £, its claw £ ; 
outer toe I, its claw § ; middle toe If its claw I ; inner toe f, its claw i. 
Weight 17 4 oz. 
