FEATHERED GIANTS 155 



dwelt in peace before the advent of man. 

 And the same things are true of the INIoas, the 

 ^pyornithes, the flightless birds of Patagonia, 

 the recent dodo of JNIauritius and the solitaire 

 of Rodriguez, each and all of which flourished 

 in places where there were no men and prac- 

 tically no other enemies. Hence we deduce 

 that absence of enemies is the prime factor in 

 the existence of flightless birds,"* although 

 presence of food is an essential, while isolation, 

 or restriction to a limited area, plays an im- 

 portant part by keeping together those birds, 

 or that race of birds, whose members show a 

 tendency to disuse their wings. It will be 

 seen that such combinations of circumstances 

 will most naturally be found on islands whose 

 geological history is such that they have had 

 no connection with adjacent continents, or 

 such a very ancient connection that they were 

 not then peopled with beasts of prey, while 

 subsequently their distance from other coun- 

 tries has prevented them from receiving such 



* Note that in Tasmania, which is very near Australia, both 

 in space and in the character of its animals, there are two car- 

 nivorous mammals, the Tasmanian " Wolf" and the Tasma- 

 nian Devil, and no Jiightless birds. 



