196 Evolution and Adaptation 



courtship have these dancing and vocal performances in nine 

 cases out of ten ? In such cases, for instance, as that of the 

 scissortail tyrant-bird, and its pyrotechnic displays, when a 

 number of couples leave their nests containing eggs and 

 young to join in a wild aerial dance ; the mad exhibitions of 

 ypecahas and ibises and the jacana's beautiful exhibition of 

 grouped wings ; the triplet dances of the spur-winged lapwing, 

 to perform which two birds already mated are compelled to 

 call in a third bird to complete the set ; the harmonious duets 

 of the oven-birds and the duets and choruses of nearly all 

 the wood-hewers, and the wing-slapping aerial displays of the 

 whistling widgeons, — will it be seriously contended that the 

 female of this species makes choice of the male able to ad- 

 minister the most vigorous and artistic slaps ? " 



"The believer in the theory would put all these cases 

 lightly aside to cite the case of the male cow-bird practising 

 antics before the female, and drawing a wide circle of melody 

 around her, etc. . . . And this was in substance what Dar- 

 win did." " How unfair the argument is based on these 

 carefully selected cases gathered from all regions of the globe 

 and often not properly reported is seen when we turn to the 

 book of nature and closely consider the habits and actions 

 of all the species inhabiting any one district.'' Hudson con- 

 cludes that he is convinced that any one who will note the 

 actions of animals for himself will reach the conviction, that 

 " conscious sexual selection on the part of the female is not 

 the cause of music and dancing performances in birds, nor 

 of the brighter colors and ornaments that distinguish the 

 male." 



The differences in color in the sexes of birds are classified 

 by Darwin as follows: (1) when the males are ornamented 

 exclusively or in a much higher degree than the females ; 

 (2) when both sexes are highly ornamented; (3) when the 

 female is more brightly colored. A few examples of each 

 sort may be chosen for illustration. 



