436 Hawkins, Sexual Selection and Bird Song. [o"t. 



less vigorous rivals, who might otherwise be chosen. The earlier 

 they can take the field, the more persistent their advances, the 

 greater their chance of ultimate success, and this because they 

 slowly instil a preference which cannot be overcome by later and 

 less virile comers." 



This fact makes it clear why many of the sober tinted birds are 

 as ardent in their love dances and displays as some of the more 

 brilliantly colored birds like the peacock and the pheasant. It 

 may also explain why some of the more beautifully colored birds 

 sing as vigorously as the duller tinted species. Their nervous 

 system is in a condition of intense stimulation through the action 

 of secretions thrown off by the sex glands. But the important 

 fact is that it completely modifies the theory of sexual selection, so 

 modifying it that there is little of the significance attributed to it 

 by Darwin and his followers remaining. The antics, display and 

 songs of birds are germinal variations which have survived and are 

 not the result of conscious or unconscious choice on the part of the 

 female. This is "borne out by the fact that birds of the most 

 sober hues affect displays of a character precisely similar in kind 

 to those of birds in which this display appears to be made for the 

 sole purpose of exhibiting to the best advantage some specially 

 modified or beautiful colored feathers." 



This view which seeks the cause of song in the internal life of 

 the bird rather than in external causes, also gives a more satis- 

 factory view of the total language of the bird, the call and alarm 

 notes, the gentle notes of the mother bird over her young and the 

 songs that are uttered outside of the mating season. The sexual 

 selection theory has fallen down, in my judgment, from the fact 

 that it has confined itself too exclusively with one short period in 

 the language of the bird. It has failed almost exclusively to 

 recognize that birds have a language which extends throughout the 

 entire year, either sign or tone language, and that there must be 

 something in the feathered creature which will account for this 

 less vigorous expression of life and needs which occur outside of the 

 mating season. It is here that the theory of germinal variations 

 comes to our assistance. Voice having originated in the hisses 

 and groans of the reptile, it was inevitable that there should be a 

 difference both of tone and vigor between the male and female 



