538 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1910. 



down all of a heap among the stumps. Here a rest is taken, and for 

 5 or 10 minutes the bird may feed quietly. Then a second flight car- 

 ries it back to the starting point or on to the end of the open space. 



Sometimes when the birds alight and clutch a twig they are so 

 exhausted that they topple over and hang upside down for a moment. 



Watching the hoatzins carefully with our stereo glasses for several 

 evenings in succession, we came to know and distinguish individual 

 birds. Two, one of which has a broken feather in the right wing, 

 and the other a 2-inch short central tail feather, are excellent flyers, 

 and, taking their flapping start from the high branch, never fail to 

 make their goal, going the whole distance and alighting easily. All 

 of the others have to rest, and one which is molting a feather in each 

 wing can achieve only about 10 yards. This one fell one evening into 

 the water at the second relay flight and half flopped half swam 

 ashore. 



One evening a hoatzin flew toward us and alighted near some hens 

 on the ground, but took wing almost instantly back to his brushwood. 

 A day or two before we came one of the birds had used a beam of the 

 porch as a perch. 



This general shifting occurs at both sunrise and sunset, and is 

 apparently always as thorough and noisy as we found it the first 

 evening of our slay. For months, we are told, it had been kept up 

 as regularly as clockwork. 



In the morning as the sun grows hotter the birds become more 

 quiet, and finally disappear, not to be seen or heard again until after- 

 noon. They spend the heat of the day sitting on their nests or 

 perched on branches in the cooler, deeper recesses of their linear 

 jungle. 



The last view of them in the morning, as the heat becomes intense, 

 or late in the evening, usually reveals them resting on the branches 

 in pairs close together. On moonlight nights, however, they are 

 active and noisy, and come into the open to feed. 



The habit of crouching or squatting down on the perch is very 

 common with the hoatzins, and it may be due to the weakness of the 

 feet and toes. I am inclined, however, to consider it in connection 

 with the general awkwardness in alighting and climbing, as a hint of 

 the inadaptibility of the large feet to the small size of the twigs and 

 branches among which it lives. Inexplicable though it may appear, 

 the hoatzin, although evidently unchanged in many respects through 

 long epochs, is far from being perfectly adapted to its present envi- 

 ronment. It has a severe struggle for existence, and the least increase 

 of am^ foe or the appearance of any new handicap would result in its 

 speedj^ extinction. 



