FEATHERED GIANTS 153 



but in this instance man is guiltless, for they 

 Uved and died long before he made his ap- 

 pearance, and the ever-convenient hypothesis 

 " change of climate " may be responsible for 

 their disappearance. 



Something, perhaps, remains to be said con- 

 cerning the causes which seem to have led to 

 the development of these giant birds, as well 

 as the reasons for their flightless condition and 

 peculiar distribution, for it will be noticed 

 that, with the exception of the African and 

 South American ostriches the great flightless 

 birds as a rule are, and were, confined to unin- 

 habited or sparsely populated islands, and this 

 is equally true of the many small, but equally 

 flightless birds. It is a seemingly harsh law 

 of nature that all living beings shall live in a 

 more or less active struggle with each other 

 and with their surroundings, and that those 

 creatures which possess some slight advantage 

 over their fellows in the matter of speed, or 

 strength, or ability to adapt themselves to sur- 

 rounding conditions, shall prosper at the ex- 

 pense of the others. In the power of flight, 

 birds have a great safeguard against changes of 



