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THE DIURNAL BIRDS OF PREY 



that original observer and Audubon as to whether vultures detected their prey by 

 sight or smell. Although the English naturalist stoutly maintained that Audubon' s 

 experiments were inconclusive, and that the turkey vulture was solely guided by 

 scent, the views of his adversary have been now very generally accepted. The 

 turkey vulture (Rhinogryphus aura} is one of several species, distinguished from 

 the black vulture by the rounded form of the tail, and by the interval between the 

 tips of the primary and secondary quills exceeding the length of the metatarsus. 



GROUP OP TURKEY VULTURES. 

 (One-sixth natural size.) 



The present species is one of the smaller representatives of the genus, measuring 

 thirty inches in length, and characterized by its plumage being generally black, 

 with the wings washed with brown; the shafts of the primaries brown on the upper 

 surface, and the red head. The allied R. perniger has the plumage all black, and 

 the head yellow; while in R. falclandicus the wings are washed with gray, and the 

 head pink; and R. urubitinga differs by its orange head and the white shafts on 

 both sides of the primaries. All these three latter species are exclusively South 



