50 THE GENETIC AND THE OPERATIVE EVIDENCE 



DISPLAY OF THE MALE. 



The antics of male birds at the mating season, their courtship 

 so-called, has played an important role in Darwin's theory of sexual 

 selection. The behavior of many birds at this time is of such a kind as 

 to suggest that the male is exhibiting his plumage before the female 

 for the "purpose" of influencing her choice. The whole parapher- 

 nalia of human psychology is imported into the situation and both the 

 consciousness of the male, his intentions so to speak, and the supposed 

 esthetic response or choice of the female is invoked. Even though it 

 be granted that the words that we must make use of, borrowed from 

 human behavior, are such as to imply much more in the direction of 

 consciousness and purpose than is desirable, and that most of the 

 behavior of animals should be stated in a more roundabout and 

 objective way, yet the theory will only work out on the assumption 

 that the female chooses in some sense the more brilliant or ornamental 

 (or effective) male, whether she is "conscious" or unconscious of 

 intention. I doubt if anyone to-day would care to defend seriously 

 the theory on the grounds of consciousness or esthetic value of the 

 exhibition, despite the fact that Darwin's language often takes this 

 turn and the less-guarded statements of some of his disciples, such as 

 Romanes, show little hesitation in anthropo-morphologizing the entire 

 situation. It is, however, not necessary for the working out of the 

 theory that this complication be introduced into it, for if the female 

 is more likely to mate with a more brilliantly colored than a less 

 brilliantly colored male, the theory may be made to apply regardless 

 of whether she is "conscious" or not of the difference to which she 

 responds. 



But there are weighty arguments against such an interpretation of 

 the behavior of the male and female during courtship. In the first 

 place, there is almost no direct evidence to show that the female mates 

 with the more ornamental male. As this is the all-essential require- 

 ment of the theory, the almost complete absence of facts in its support 

 leaves the theory resting on a theoretical assumption. It can scarcely 

 pass unnoticed that while there exists a large mass of data describing 

 the secondary sexual characters, there is practically nothing in this 

 accumulation to show that the female makes her selection on differ- 

 ences in coloration or ornamentation. And on the other hand, there is 

 some evidence showing that the female is ready to succumb to the 

 aggressiveness of the male rather than that she "chooses" him. 



The behavior of the male under sexual excitement is often described 

 to be of a kind to exhibit before the female his peculiar adornments. 

 That the "purpose" of his exhibition is to show himself off before the 

 female may be conceded, with reservations as to what is meant here 

 by "purpose." That the male is conscious of the probable results of his 

 conduct is scarcely probable the first time he courted; but that he may 



