RAPTORES. 89 



besides this keeping in check of over production, 

 by the preying of one tribe upon a weaker race, 

 another provision has been considered, that of 

 the removal of animal matter where heat renders 

 putridity when life is extinct almost instan- 

 taneous, and where there is commonly, from 

 various circumstances, at the same time a great 

 expense of animal life. It is thus that we find 

 in the warmer climates the most abundant distri- 

 bution of the vultures, which decrease as they 

 reach the north, and in our own country cease, 

 with the rare examples of the species with which 

 our present volume commences. The Falconidae, 

 again, are more universal in their proportional 

 distribution, but we find the stronger or more 

 typical species abounding in the temperate 

 regions ; while in those countries possessing a 

 greater degree of heat, and between the tropics, 

 we see the forms more variously distributed, and 

 a greater proportion of those small or very 

 weakly formed species, which serve to keep in 

 check the multitudes of small lizards and reptiles, 

 with the countless hosts of insects which are 

 there so extremely destructive ; and it is remark- 

 able that a most formidable tribe, the Gryllidae, 

 to which the locust belongs, is one of the most 

 eagerly hunted after by those smaller falcons. 

 The Strigidae, or owls, are also universal in their 

 distribution, and prey mostly on the smaller 



