260 BULLETIN 113, UNITED STATES NATIONAL MUSEUM. 



Young. — In the same paper Mr. Jones gives us the results of his 

 observations on the behavior of the young terns in the following 

 words : 



There is no uniformity in the development of the instinct to assume protec- 

 tive attitudes. With some young there is no evidence of such an instinct 

 while they remain in the nest, while with others there seems to be almost as 

 soon as the shell is cast. All of the young from the beginning of the pin- 

 feathers gave evidence of the instinct well developed. Some young left the 

 nest two days after hatching; some remained for four days. When partly 

 feathered birds on the uplands were taken from their hiding places in the grass 

 or bushes their tendency was to try to run away instead of hiding again when 

 replaced on the ground. Those on the beach treated the same way would in- 

 variably take to the water if not prevented. Even the young upon which the 

 pinfeathers were barely showing frequently took to the water and swam 

 readily. In hiding the birds were content to emulate the ostrich, hiding only 

 the head and often leaving the whole body exposed. They were always careful, 

 however, to keep the white underparts well concealed. 



Unlike the gulls, the terns do not swallow the food and then regurgitate for 

 the young, but carry the fish in the beak directly to the young. 

 After studying the feeding process at close range for some time I be- 

 came convinced that the old birds do not stuff the fish down the throat of 

 the young, but only thrust its head into the mouth far enough for the throat 

 muscles to grip it, when the young bird swallows for himself. The sand launce 

 {Ammodytes americanus) was the chief fish food, probably because it is so soft 

 and easily digested. A 4-inch fish could not manage to get wholly inside a 

 4-inch bird, so the tail was left sticking out for future consumption. Even with 

 the young able to fly the fish's head rested in the primitive gizzard, while the 

 tail was scarcely more than concealed in the throat. Mr. Field induced one 

 Muskeget young common tern to part with his dinner of two young herrings 

 and one sand launce. Usually but a single fish was found in the digestive 

 tract of the young. 



The downy young merely raised their heads and opened their mouths for 

 food, when very hungry uttering a faint peep, but the young ones able to 

 fly were made to dance for their dinner. With widely gaping mouth and 

 wings held akimbo, they executed a surprisingly fine clog to their own piercing 

 music. In one case a young bird called for lunch just 20 minutes after receiving 

 a good-sized fish. He was not fed, however, until half an hour after his last 

 lunch. I have repeatedly seen the old birds swallow three and four sand 

 launces in rapid succession. This colony of 1,500 old birds and their 1,500 

 young must consume great quantities of the sand launce, yet the supply does 

 not seem to diminish. 



It was interesting to watch the old birds come in with a fish dangling from 

 the beak. As it passed close along the beach each young bird in turn clamored 

 for the morsel. When the old bird approached the place where its young had 

 been last seen it skimmed above the stones, halting now and then before a 

 particularly vociferous youngster, then either passed on or circled back to 

 look farther, finally either finding its own young or going to another place 

 where another young had been left. I was eager to know how the old birds 

 could recognize their own offspring among the multitude which looked exactly 

 alike to me. It seemed incredible that they depended upon sight, or why 

 should they almost actually touch the young each time before deciding the 

 matter? I was forced to the conclusion that the sense of smell must play an. 

 important part in the final determination. 



