COURTSHIP IN BIRDS 255 



tendency of the highly civilized male to revert 

 to brilliant display of clothing is shown in his 

 fondness for military finery and for striking 

 colors when he is freed from the restraining hand 

 of convention, as witness the cowboy and the 

 sportsman. 



In both bird and man the display of bright 

 colors and attractive patterns, the dance and the 

 song, even if of courtship origin and competitive 

 in character, may lose the conscious, sexual side 

 and be continued at other times for mere pleas- 

 ure, in other words the original incentive for dis- 

 play, song and dance may be entirely lost, but 

 that does not seem to me to be any argument 

 against the theory of sexual selection. 



The explanation of the brilliant colors of male 

 birds on a mere physico-chemical basis due to 

 exuberance of vitality, the maleness of the males, 

 or the stimulation of the hormones in the court- 

 ship season fails to account for the fact that the 

 brilliance of display in this season may occur 

 without the growth of new feathers, but merely 

 by the wearing down of old feathers and the un- 

 veiling of concealed patterns. This is true in 



