278 The Naturalist in La Plata. 



music unparalleled among birds possessing a similar 

 habit. While singing he passes from bush to bush, 

 sometimes delaying a few moments on and at others 

 just touching the summits, and at times sinking out 

 of sight in the foliage : then, in an access of rap- 

 ture, soaring vertically to a height of a hundred 

 feet, with measured wing-beats, like those of a heron : 

 or, mounting suddenly in a wild, hurried zigzag, 

 then slowly circling downwards, to sit at last with 

 tail outspread fan wise, and vans, glistening white 

 in the sunshine, expanded and vibrating, or waved 

 languidly up and down, with a motion like that of 

 some broad-winged butterfly at rest on a flower. 



I wish now to put this question : What relation 

 that we can see or imagine to the passion of love 

 and the business of courtship, have these dancing 

 and vocal performances in nine cases out of ten? 

 In such cases, for instance, as that of the scissors- 

 tail tyrant-bird, and its pyrotechnic evening displays, 

 when a number of couples leave their nests con- 

 taining eggs and young to join in a wild aerial 

 dance : the mad exhibitions of ypecahas and ibises, 

 and the jacanas' beautiful exhibition of grouped 

 wings : the triplet dances of the spur- winged lap- 

 wing, 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 



