336 OUR SEARCH FOR A WILDERNESS. 



vertebrae, the object it had picked up being held meanwhile 

 in its bill. (Fig. 137.) 



The wild Curassow soon drops whatever it has picked up 

 and claps its wings together seven or eight times over its 

 back, making a loud slapping sound. It then turns its back 

 on its rival in the tree, plucks nervously at the wings, right 

 and left, for a full minute or longer, and then reaches con- 

 vulsively forward several times, with its head and neck, the 

 bill being wide open, gulping in a great quantity of air. Its 

 abdominal air-sacs swell, its wings are lowered and rounded 

 out until the bird appears half as large again as usual. Thus 

 it stands, half squatting with lowered head and tail, and 

 within a period of five to ten seconds utters usually four notes 

 of the deepest and most penetrating character. Now that I 

 am within a few yards, they sound no louder than when sev- 

 eral hundred yards away. The exertion put forth shows this 

 vocal effort to be a strenuous one, and at the second perform- 

 ance the tones are rather low and confused. But the normal 

 utterance, this climax of the whole challenge, is as follows : 





This may be imitated by anyone with a deep bass voice by 

 humming the syllables Um } urn, um-um-um, to the notes 

 as I have written them. 



During this period the actor, as observed in the captive 

 specimen, seems almost in a trance, standing with half closed 

 eyes, oblivious even of a hand resting on the feathers of his 

 back, and the recovery is slow, the bird seeming dazed for a 

 short time. 



As I lay concealed in the Guiana forest, the whole per- 

 formance was repeated five times in twelve minutes, the 



