The Behavior of Noddy and Sooty Terns. 219 



sands of observations did I see a young tern begging food from a stranger. 

 The statement has often been made by certain observers that young gulls 

 feed indiscriminately from any adult which happens to be near. Such is 

 certainly not the case among the sooty terns. 

 In summarizing, we may say: 



( 1 ) The presence of the young changes the general disposition of the 

 parents; for the first two or three days after the appearance of the young 

 the parents are more ferocious, but as the young bird gathers strength and 

 can get away from danger, the parents become more wary and leave the nest 

 upon the slightest disturbance. In this latter respect, as is similarly the case 

 with the noddies, they, as it were, tend to revert to the habits formerly ex- 

 hibited during the laying period. 



(2) A tremendous change appears in their feeding habits. During the 

 brooding period the birds apparently are away all day; at the appearance of 

 the young conditions are so changed that the birds relieve each other at the 

 nest at intervals varying from 4 to 7 hours. 



(3) The birds have more leisure; they utilize this leisure in collecting 

 upon the beach for sunning. 



(4) The birds become exhausted in caring for the young. 



PRELIMINARY ATTEMPTS AT CONTROLLING THE REACTIONS OF 



ADULT BIRDS. 



The experimental part of my work centered mainly around the young 

 terns, because I could rear them by hand and could control their reactions 

 through hunger. An experimental study of the adult birds is beset with 

 many difficulties. The previous part of my work shows that until the egg 

 is laid the terns can not be approached closely for experimental purposes. 

 Only a short month was open to nie after the egg was laid before the young 

 appeared. After the young appeared, practically all of my time was devoted 

 to them. From the middle of May until the middle of June, however, I 

 had time to try the experiments upon the adult birds which are reported 

 below at some length. I found that a month was too short a time in which 

 to capture and tame adult birds for experimental purposes. In captivity, the 

 birds are wild and restless, but unless they are in captivity they refuse to eat 

 even live fish, even when the fish are placed near the nest. As was shown 

 earlier, in the discussion of the feeding habits of these birds, the natural 

 stimulus to the feeding reaction is the sight of schools of minnows jumping 

 over the surface of the water. I may say in passing, however, that two 

 sooties with broken wings learned to appear at my experimental cages 

 whenever I fed the young terns. These two birds learned to eat both live 

 and motionless fish either from the hand or from a dish. I think it not 

 improbable that, had time permitted, I could have captured the birds and 

 taught them to feed from the hand. Had this been done, hunger could then 



