The Behavior of Noddy and Sooty Terns. 217 



lay quiet and hidden for 3 hours near a large group of nests which was 

 situated under some very dense bushes. The adult would circle over the 

 area and give a call ; it would be answered and random movements would 

 give place to direct. The bird would steer immediately for the source of the 

 call. By peculiar chuckling sounds, which are emitted at this period when 

 mates return, one can be sure that the proper nest has been located. I ob- 

 served this many times during one evening. After the young were 20 to 30 

 days old I have heard the young birds answer the call of the parent back 

 and forth a dozen times before the latter actually alighted. 



The parents alternately feed the young, but instead of a diurnal period 

 of feeding, such as the parents have before the appearance of the young, the 

 intervals vary anywhere from 4 to 7 hours. My observations are few on 

 this point. 



Though the parents feed the young at any hour of the day, feeding can 

 be most easily observed at dusk. It has already been mentioned that the 

 sooties hurry home at nightfall in great numbers. From 4 until 8 p. m. this 

 feeding process keeps the island in commotion. The feeding of the young 

 birds has many interested spectators. While I have never seen the terns from 

 the neighboring nests, which may be observing the process, attempt to rob the 

 young bird, I judge from the actions of the feeding parent that such is 

 occasionally the case. If the parent happens to disgorge more than the 

 young tern can take into its beak and the food is allowed to fall to the 

 ground, it is ludicrous to watch the rapidity with which the parent picks up 

 the food and reswallows it. Oftentimes the mate of the feeding parent is 

 near ; its role is a purely passive one, except when the " spectators " attempt 

 to approach too near. Its part is then to assist in warding them off. 



Neither young nor old is quiet during this period of the nesting season. 

 On the contrary, the noise is practically doubled. In addition to the ordi- 

 nary sounds made by the adults and the new cries which are added at this 

 time, there is present the high-pitched, insistent " peep-peep " of the young 

 terns. Momentarily the sounds of the adults will cease and the cries of the 

 little ones remind one very strongly of a poultry-yard on a tremendous scale. 



A reaction very similar to the " sunning reaction "of the noddies, while 

 present to some extent before the appearance of the young, now shows itself 

 in completed form. As may be judged from the feeding habits of brood- 

 ing birds, practically only a half of the total number of birds is present on the 

 island during the day, and that half is busied in brooding the eggs. Conse- 

 quently there is little leisure at this time in the sooty colony. After the 

 appearance of the young, the number of birds present on the island at any 

 one time is much larger. When R returns to feed the young, 5' usually 

 leaves the nest, but as in the case of the noddies does not always leave 

 immediately to feed. They collect upon the beach and sun themselves, preen- 

 ing their feathers and standing idly about in a way which is quite similar to 



