242 BULLETIN 113, UNITED STATES NATIONAL MUSEUM. 



my attention and interest. After the young leave the nest and its vicinity they 

 wander about aimlessly and may be at widely different places at two visits of 

 the old birds. Hence it is often a serious question on the part of the parent 

 how to find its offspring. Abundant opportunity was afforded for studying this 

 question. Old birds with young which had left the nest, when coming in with a 

 fish, stooped to examine each group of young in turn until a young bird, appar- 

 ently its own, was found, when the old bird alighted. Immediately the young- 

 ster began to dance and call vociferously, but not until the old one had touched 

 the young one with its forehead was the question decided. Often this minute 

 inspection was immediately followed by the departure of the old bird without 

 delivering the fish, the quest for its own young being renewed. It thus became 

 clear that sight alone was not depended upon for recognition, but that the final 

 decision rested upon the sense of smell. Sometimes the quest resulted in failure, 

 when the old bird swallowed the fish. The evidence seemed to indicate that 

 these terns feed only their own young. 



By the 1st of July on Muskeget probably the majority of the young 

 terns have hatched in nests which have not been disturbed. Under 

 favorable weather conditions the eggs are often left uncovered, the 

 sun and the warm sand supplying the proper amount of heat; but 

 the birds seem to be able to judge these conditions quite accurately, 

 for in cold, cloudy, or rainy weather, when the eggs might become 

 chilled, or, on the other hand, when the sun is too hot for them, I 

 have always found the birds anxious to return to their nests and 

 protect their eggs. I think they always incubate at night. Terns 

 are seldom seen on their nests because they are timid and restless, 

 but they will soon return to them if the intruder remains quietly 

 concealed at a safe distance. The hatching process is often slow and 

 laborious, a day or more intervening between the time when the horny 

 tip of the bill makes a small hole near the larger end of the egg and 

 the actual hatching time, when the weak, wet little chick emerges 

 from the shell. It dries off within a few hours and remains in the 

 nest for two or three days. Its eyes are open at birth, but it is not 

 fed until the second day. It is fed on small fish from the very first, 

 which it swallows head first. When three or four days old the young 

 chick becomes very lively, running about rapidly, hiding in the grass 

 or between stones, or even lying flat on the sand, where its protective 

 coloring helps to conceal it. It seems to realize this fact, for I have 

 often seen one remain perfectly motionless until it felt sure it was 

 discovered, after which its capture was far from easy. Parents must 

 experience considerable difficulty in finding their own young, and still 

 more trouble in protecting them against inclement weather. On 

 July 4, 1903, I noticed evidences of great mortality among the very 

 young chicks on Muskeget; I found hundreds of their little dead 

 bodies scattered over the island, drying in the sun, sometimes two or 

 three in one nest, and once I saw the dead body of an adult tern 

 covering the bodies of two young in the nest. Captain Gibbs, of the 

 life-saving station, thought that they were killed by exposure to pro- 



