THE PRINCIPAL BIRD GROUPS 91 



Hawks, Falcons, Harriers, and allied birds (Fal- 

 conidae) ; and lastly the Ospreys (Pandionidae). 

 The American Vultures present various important 

 anatomical differences from their Old World re- 

 presentatives, among which may be mentioned 

 the perforated nostrils, the small elevated hallux, 

 and the absence of syringeal muscles. Included 

 in this sub-order is the remarkable Condor. Of 

 the Old World sub-order Accipitres, the most 

 aberrant form is the Secretary Bird, a long-legged 

 bird, more like a Crane than a Raptor in appear- 

 ance, standing more than a yard high, with a con- 

 spicuous nuchal crest, and the two central tail 

 feathers more than double the length of the 

 rest. Its partiality for snakes and other reptiles 

 ensures it protection from mxan. The Old World 

 Vultures are externally characterised by the 

 absence of feathers from the head, the frequent 

 presence of a ruif round the neck, blunt claws, 

 and the absence of a ^' tooth" or notch in the 

 hooked bill. They are for the most part eaters 

 of carrion, and though gifted with marvellous 

 powers of flight, are comparatively sluggish birds. 

 They build huge nests of sticks, &c., and their 

 eggs, one or two in number, are white or vari- 

 ously marked with reddish-brown and grey. The 

 next family is by far the most extensive, and 



