The Tortugas Tern Colony 



of the crop will be deposited on the rim of the nest and this will be 

 eaten by the female. 



The young are fed by both parents upon food disgorged in a similar 

 manner. They are among the most helpless of young wild birds, being 

 absolutely dependent upon their parents for food until they are over three 

 months old. 



For the first two months they remain in the nest; after that they are 

 in and out of it, resting near by on branches, and when frightened de- 

 scending to the ground and seeking shelter among the roots and in 

 neighboring tufts of grass. 



It is a rather humorous sight 

 to see one of these great over- 

 grown babies with an adult appetite 

 patiently waiting for meals to be 

 brought and scolding vigorously 

 when the supply has given out. 

 They are fully four-fifths the size 

 of the adult before competent to 

 care for themselves. 



Normally but one egg is laid by 

 a pair, but if it is injured or lost its 

 place is promptly taken by another. 

 One of the nests, during a storm, 

 was broken, and the egg, then two 

 weeks old, rolled into such a posi- 

 tion that it was impossible for the 

 birds to get at it. The following 

 day the birds built a superstructure 

 to the nest, and within a week 

 another egg was laid, and their 

 housekeeping proceeded without 

 further interruptions. 



This ability to control the size 

 of the family presents a physiological 

 problem of great interest. Normally, it consists of one young ; but the 

 possible number is apparently very large, as the same nest can be robbed 

 many times of its egg and yet another will be deposited. 



Another fact of great interest is the psychological change in the birds' 

 characters as evidenced by their attitude toward man during the breed- 

 ing season. These birds live on the high sea two-thirds of the year, and 

 then are not easy to obtain with a shot-gun ; but, when brooding, the 

 mother-bird can be approached and easily taken in the hand. Toward 

 the end of the season they can be picked up and handled, and when 



