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 ofa heron : 
or, mounting suddenly in a wild, hurried zigzag, 
then slowly circling downwards, to sit at last with 
tail outspread fanwise, 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 aérial 
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 ina 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 aérial displays of the 
whistling widgeons; will it be seriously contended 
that the female of this species makes choice of the 
