138 THE COURTSHIP OF ANIMALS 



assumed too much, that it assumed a common and uniform 

 standard of perfection shared by all the females concerned 

 in the selection, which is indeed assuming too much. 

 But his own theory was no more satisfactory. Indeed 

 it was very much less so, for he contended that these 

 various exaggerations of colour and form are to be 

 regarded simply as evidences of a superabundant vitality, 

 though there is no evidence that " superabundant vitality," 

 if it exists, is a transmissible character 



The revised version of the Sexual Selection theory 

 advanced in these pages is largely inspired by the work 

 of Mr. H. Eliot Howard who, in his Monograph on the 

 British Warblers, has not only added very materially 

 to our knowledge of the life-histories of these birds, during 

 the reproductive period, but has also done much — both 

 in the direction of destructive, and constructive criticism, 

 of generally accepted conceptions on this head — to set 

 us on the right track for further research. 



A study of his work leaves one with the conviction 

 that, while these birds exhibit what we may call a nascent 

 intelligence, their actions, on the whole, may be described 

 as instinctive, or congenitally definite. That is to say, 

 they follow one another in definite sequence. Hence we 

 must regard each new phase in the chain of events apper- 

 taining to the reproductive cycle, as following one another 

 in a definite sequence, so that any break therein throws 

 the orderly performance of the necessary acts out of gear. 

 There is no realization of what reproduction means, no 

 deliberate striving to achieve that end. Each new phase 

 brings its own set of associations and sets a new train 

 of actions in motion, which are performed mechanically. 

 For instance, these Warblers, like hosts of other species 

 under similar circumstances, are scrupulously careful to 



