114 WHAT EVOLUTION IS 



birds showed that the survivors were 

 less variable than those that perished. 

 The birds that died were, in many 

 cases, extreme individuals. For in- 

 stance, they more frequently had 

 large bodies combined with small 

 wings, or the reverse, than the sur- 

 vivors had. Hence they represented 

 conditions in which it might be said 

 that there was too much power or too 

 little power for the wing surface and 

 the like. This disadvantageous ten- 

 dency was in general the cause of 

 their death. One may therefore con- 

 clude that, under the severe circum- 

 stances mentioned, elimination was 

 not haphazard but rather, as would 

 be expected, that the least fitted birds 

 succumbed and the best fitted sur- 

 vived. In this rather crude way, evi- 

 dence of a selective capacity in nature 

 has been obtained, and from instances 

 of this kind, it is fair to conclude that 



