88 FALCONID^. 



the one feeding the other. The young are at first covered 

 with buff-coloured down. Their next covering exhibits 

 the pure white and black of the old birds, but without 

 any of the glossy purplish tints of the latter. The tail, 

 which at first is but slightly forked, becomes more so in a 

 few weeks, and at the approach of autumn exhibits little 

 difference from that of the adult birds. The plumage 

 is completed the first spring. Only one brood is raised 

 in the season. The species leaves the United States in 

 the beginning of September, moving off in flocks, which 

 are formed immediately after the breeding season is over." 

 The figure and description here given were taken from 

 a preserved specimen in the Museum of the Zoological 

 Society, the whole length of which was twenty inches ; 

 the beak bluish black, the cere lighter blue, the irides 

 dark ; the whole of the head, neck, breast, belly, under- 

 surface of the wing, sides of the body, thighs, and under 

 tail-coverts, pure white ; the back, wing primaries, secon- 

 daries, upper tail-coverts, and tail-feathers, black, with a 

 purplish metallic lustre ; the tertials black on the outer 

 webs, but patched with pure white on the inner ; tail very 

 deeply forked ; legs and toes greenish blue ; claws faded 

 orange colour. 



