74 EVERYDAY BIRDS 



But the looker-on is likely to be quite as much 

 impressed by what he sees as by what he hears. 

 During the whole performance, but especially 

 during the latter part of it, the bird is engaged 

 in the most violent contortions, suggestive of 

 nothing but a patient sufEering from uncontrol- 

 lable nausea. Moreover, as soon as the prelimi- 

 nary hiccoughs begin, the lower throat or breast 

 is seen to be swelling ; the dilatation grows 

 larger and larger till the pumping is well under 

 way, and so far as my companion and I could 

 detect, does not subside in the least until the 

 noises have ceased altogether. 



How are the unique, outlandish notes pro- 

 duced? I cannot profess to know. Our opinion 

 was that the bird swallowed air into his gullet, 

 gulping it down with each snap of the beak. To 

 all appearance it was necessary for him to inflate 

 the crop in this way before he could pump, or 

 boom. As to how much of the grand booming 

 was connected with the swallowing of the air, 

 and how much, if any, with the expulsion of it, 

 my friend and I did not agree, and of course 

 neither of us could do more than guess. 



I made some experiments afterwards, by way 

 of imitating the noises ; and these experiments, 

 together with the fact that the grand booming 

 seemed to be really nothing more than a develop- 



