FAMILY GYPOGERANID^E ; SECRETARY. 413 



back of its head ; which reminded them of the pen stuck behind 

 the ear, according to the custom of writing-clerks. The remark- 

 able feature in its structure, by which it is distinguished from all 

 other Raptores, is the extraordinary length of its tarsi, which 

 raise its body above the ground, in the manner of that of the 

 Wading Birds. This conformation adapts it to its peculiar in- 

 stincts ; which lead it to prey upon Serpents and other poisonous 

 reptiles, in search of which it strides over the dry open plains 

 frequented by them. It is further armed with spurs on the 

 elbow -joints of the wings ; and these are efficient organs of de- 

 fence, by which it parries the attempts made by its prey to 

 wound it by its venomous bite, and by successive blows of which 

 it weakens its foe, destroying it at last by a stroke of its bill, 

 that splits open its enemy's skull. Le Vaillant mentions, that 

 having killed a Secretary, which he had seen to vanquish a Ser- 

 pent, he found in its crop eleven rather large lizards, three ser- 

 pents of an arm's length, and eleven small tortoises very entire, 

 all of which had received the stroke on the head ; as well as a 

 number of locusts, beetles, and other insects, very little injured. 

 The Secretary builds its nest on high trees, or in dense thickets ; 

 and is not at all disposed to associate with its fellows. 



376. We have seen that the Birds of the family FALCONID^E 

 have for their office to regulate the numbers of living Birds and 

 small Quadrupeds ; and that their head-quarters are in the cold 

 and temperate regions of the globe. The Vultures, and other 

 Birds of the family VULTURIDJE, on the other hand, are the 

 appointed cleansers of the earth from the dead bodies of such 

 animals as have perished from other causes ; and their head- 

 quarters are between the tropics, few of them having any exten- 

 sive range to the north or south of these lines. Still, however, 

 they are for the most part inhabitants of mountainous regions ; 

 and their abodes are often on the confines of perpetual snow. 

 They execute that kind of duty, which no animals but Birds 

 could perform ; for although the Hyaenas and Jackals may well 

 effect the removal of decomposing carcasses from the open and 

 level country, the dense and tangled forests of tropical regions, 



