Nest Life of the Catbird 171 



At 9:28 the next morning (July 32) the female partly rose 

 from the nest displaying the separating halves of the last 

 egg. The process was practically the same as that previous- 

 ly described. The parent again took the smaller piece of the 

 shell first. She then returned and picked at the remaining 

 piece two or three times and brooded for twelve minutes be- 

 fore any other move was made. At the end of that time she 

 rose in the nest, picked the bird up in the shell and then let 

 it down again. The shell then came away from the nestling 

 and was removed, the small pieces being picked carefully 

 from the nest as before. 



In these three instances the hatching process seems to have 

 been much the same. In each case it was due to the com- 

 bined efforts of the parent and the young bird within the 

 egg. In the first case the initial movement may have come 

 from the female while in the last two it originated with the 

 young. In all three the female assisted by pecking at the 

 egg and by removing the broken shell from the nestling much 

 sooner than it would have been able to free itself from the 

 pieces. 



In the Sioux City study the young were marked with string 

 on the leg. One nestling A, being without any string, B 

 with a brown string, and C, a white string. In nest B . Smith 

 marked the first one hatched with blue dye and the second 

 one which died in a short time was not marked at all. In 

 nest C two methods were tried. The nestlings were first 

 marked with aniline dyes. In this way the first one hatched 

 was marked blue, the second with brown, and the third was 

 not marked at all by this method. The dyes did not give sat- 

 isfaction as they had to be renewed several times a day to 

 render the colors distinct to an observer in the blind altho 

 they could be readily distinguished on a closer examination. 

 After this method was tried, strings were fastened to the 

 legs of the young and they will be designated as Blue, 

 Brown, and White. 



Marking the Young. 



