144 THE BIOLOGY OF THE SEASONS 



themselves in an unwonted light. Their whole nature 

 appears changed, for all their movements are more active, 

 more excited than usual, and their conduct differs from their 

 ordinary behaviour in every respect ; they are possessed by 

 an intoxication which increases the elasticity of their nature 

 to such a degree that no flagging is ever perceptible. They 

 deprive themselves of sleep, or reduce it to a minimum with- 

 out weariness, and while awake they exert all their powers to 

 the utmost without fatigue." 



It is all like a prototype and at the same time a caricature 

 of human wooing. 



THEORY OF PREFERENTIAL MATING 



Darwin believed that the female birds exercised a real 

 choice, yielding themselves to those cocks that pleased them 

 most. He also believed that the choice was definitely based 

 upon particular excellences of the chosen mates fineness of 

 song, exuberance of plumage, agility in flight, winsomeness of 

 dance, or impressiveness in parade. He gave the hen-birds 

 credit for aesthetic preferences, and his general theory was 

 that by persistently selecting the males who varied in the 

 direction of finer song and brighter plumage, they had gradu- 

 ally evolved these qualities to a high pitch of perfection. 

 " The females," he said, " have, by a long selection of the 

 more attractive males, added to their beauty and other 

 attractive qualities. If man can in a short time give 

 elegant carriage and beauty to his bantams, according to 

 his standard of beauty, I can see no reason to doubt that 

 female birds, by selecting during thousands of generations 

 the most melodious or beautiful males, according to their 

 standard of beauty, might produce a marked effect." In 

 short, constitutional variations are common, and a variation 

 very advantageous to its possessor in courtship runs a fair 



