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



It is too superficial a theory to satisfy the modern mind. We are 

 compelled to ask the question, why does the male bird have more 

 surplus energy than the female? This question throws us back to a 

 consideration of the fundamental difference between the male and 

 the female. There is only one answer to that question. The male 

 sings more vigorously because he is a male, in other words because 

 there is some fundamental difference between the sexes. 



Karl Groos has contributed one very serious modification of the 

 Darwinian theory which has not been given sufficient consideration 

 by ornithologists, namely, that the song and antics of the male 

 bird are not for the purpose of compelling her choice by the female 

 but to overcome and break down her instinctive coyness. Nature 

 has given the female coyness as a dam to nature's impulses to 

 prevent the "too early and too frequent yielding to the sexual 

 impulse." A high degree of excitement is necessary to break this 

 down and hence the necessity for all the vigorous songs and antics 

 of the male. 



I am confident that this theory is destined to find wider accept- 

 ance in the future than it has in the past, indeed, that a large part 

 of the song of birds before the nesting season is for the purpose of 

 breaking down the reluctance of the female rather than compelling 

 her choice of a particular male. At Bakersfield, California, I spent 

 an hour watching a male Flicker sitting on a small limb a foot or 

 more above his mate while both birds went through motions that 

 were interesting and at times almost ludicrous. The proud male 

 would extend his head in a line with his body, then turn both body 

 and neck first to one side and then the other, like a weather vane 

 hung on a central shaft, at the same time jerking his head back and 

 forth in a sort of kick-up motion, and pouring out all the time a 

 quick succession of notes which might be represented by the words 

 pick-up, pick-up, pick-up, closing the whole performance by a 

 right-about-face, when he would rest a minute and repeat the 

 process. His less gaily colored mate was not so vigorous in her 

 antics as her proud lord nor did she indulge in them so frequently 

 but it was evident that he was making his impression and she could 

 not refrain from expressing her feelings. I was certain that these 

 birds had mated their lives "for better, for worse." Hence the 

 love song could not have been for the purpose of mating but to 



