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, Falco 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 white 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; tail 7y|; bill along the ridge ■J|; 

 along the edge of lower mandible l-/ f ; tarsus l-^; first toe T 7 2, its claw f; 

 second toe y|, its claw ||; third toe -*, its claw -f|; fourth toe ^, its claw r T %. 

 Weight 14 oz. 



Adult Female. 



The female is rather larger than the male, but in other respects similar. 



Length to end of tail 16f inches, to end of wings 15f, to end of claws 

 12$; extent of wings 41|; tail S; wing from flexure 13-^; bill along the ridge 

 1^, along the edge of lower mandible l£; tarsus 1$; hind toe f, its claw $; 

 outer toe ^, its claw £; middle toe If, its claw -§; inner toe £, its claw f. 

 Weight 17i oz. 



