334 On the Habits of the Hoatzin. 



these were from half to three quarters of an inch in 

 length. 



From the nature of the food contents, I was led to believe 

 that the time of day at which the young birds were procured 

 made a considerable difference as to the state oi: the food 

 in the crop. The feeding-time of the adult birds is 

 evidently the early and late parts of the day, at which time 

 their crops are found to contain, and especially at their an- 

 terior part, quantities of large pieces of young leaves, and 

 sometimes these pieces consist of a half or nearly an entire 

 leaf, almost unaltered — the pieces packed against and be- 

 tween the wrinkled surface of the immensely developed 

 ruga being, however, seldom of this nature. Early in the 

 morning and late in the afternoon, before feeding-time, the 

 contents of the crop are but little recognizable, the fragments 

 being considerably altered, as well doubtless by the peculiar 

 warmth and moisture as by the special action of its strong 

 rugae. If the nestlings are fed by the parent birds with 

 small portions of the young foliage, which, owing to its soft- 

 ness and delicacy, the weakest condition of their jaws would 

 allow them to tear from the bills of their parents, either in 

 large or small portions, the long resting-time during the 

 night and the middle of the day would be sufficient to cause 

 a change in the leaf-pieces corresponding to that produced 

 in the adult birds. 



The nestlings, even when quite small, are frequently found, 

 far away from any nest, climbing, by the help of their clawed 

 wings, after the parent birds during their feeding-time ; and 

 it seems a most likely thing, though 1 have never directly 

 observed it, that they are then fed with the tender leaves 

 which the parents pluck for them. Failing the proof from 

 direct observation, there seems to be no necessity for con- 

 cluding that the nestlings are fed by a regurgitation of the 

 food-mass from the crop of the adult birds, as Dr. Young has 

 been inclined to think likely ('Notes from the Leyden Mu- 

 seum,' vol. x. p. 171). 



It was a very noticeable thing, during the various months 

 when the birds were under my observation, that a very 



