NOTES ON HOATZINS 179 



The nestling hoatzin could see distinctly beneath the 

 surface and never bumped into submerged branches nor the 

 sides of its small pool, but avoided them with a quick turn. 

 This was achieved either by a stronger stroke of one wing, 

 or by a sudden flick of the long feather sheaths of the tail. 

 Several times I saw birds turn well over on their sides, ca- 

 reening sharply as they banked on some short turn to the 

 left or right. Twenty feet was the greatest distance I saw 

 them swim, but were they forced to do so they could undoubt- 

 edly cover several times this distance. 



Nothing has been definitely recorded of the method of 

 feeding of the young hoatzins, but this time at a distance 

 of less than fifteen feet, I was able to watch the parent feed- 

 ing the nestling by regurgitation. It was quite a leisurely 

 affair. The old bird would rise on the nest and without fur- 

 ther shifting her position, reach down beneath her and open 

 her bill. The nestling craned his neck upward and thrust 

 his head well down her throat, where he pecked and fed for 

 ten to twenty seconds. Then she righted herself, swallowed 

 several times, shook her head and the feeding was ended. 



The keel of the breastbone of these birds is greatly re- 

 duced by the abnormally large crop, but the small extent 

 of keel which does succeed in reaching the skin is in constant 

 use as a perching cushion. Even in the nestlings it is splayed 

 out and the skin over it somewhat calloused by the constant 

 pressure of the bird's body against the twigs and branches. 



A fact which was quite new to me was the molting of 

 the wing claws. In the two weeks' old nestling these were 

 as curved and sharp as the claws of a cat. Examination of 

 young birds in various stages of growth showed that the 

 claws on both thumb and fore-finger are shed at least twice 

 in the first eight months. This reminded one of the several 

 renewals of the flight feathers in the first few months of 

 life of some other birds, and the cause is doubtless the same 

 the constant use of the claws and the feathers resulting 

 in considerable wear in a very short time, which for the 



