Racket-tailed Humming-bird 97 



latter locality there was nothing which could apparently 

 attract the birds it was an open plateau, with some scat- 

 tered bushes, which offered a minimum of shade. There 

 were no flowers, and the birds only assembled there to go 

 through their evolutions," 



Two young males would arrest their flight in the air, 

 vis-a-vis, with the body suspended in a vertical position, 

 opening their tails, turn and turn about, so that the outer 

 tail-feathers with their rackets formed a straight line 

 perpendicular to the long axis of the bird, as they darted 

 from side to side. Each time that the bird opened its tail, 

 was heard a little dry sound like the snapping noise made 

 by two finger-nails or the sound made in shutting a 

 watch. 



"My later observations," says Mr. Stolzmann,"made on the 

 Manakins, and the analogy of the stiffening of the secondary 

 quills, induce me to believe that it is the mutual concussion 

 of these stiffened feathers which makes the sound that which 

 one can hear at ten paces' distance. The elongated under 

 tail-coverts rest in their natural position, being independent 

 of the system of the muscles of the rump, which are strongly 

 developed. 



" The manoeuvre lasts for quite twenty seconds. It is 

 ordinarily executed by two j'oung males ; but sometimes, as 

 I have already remarked, a larger number take part in it. 

 One can nearly always hear the voice of a female bird in the 

 neighbourhood. At Tamiapampa ten minutes did not pass 

 but these manoeuvres were repeated, and the birds have 

 their chosen places for the performance. On the plateau 

 mentioned above they had a favourite thicket. At Osmal 

 there were two such, and the birds seldom went through 

 their manoeuvres elsewhere. By concealing oneself quietly 

 in the neighbourhood I could observe them for as long as I 

 wished." 



Mr. Stolzmann speaks of another evolution still more 



