Olive-backed Thrush at Summer Home. 123 



gurgitation, ate the excrement, burrowed under the young, 

 ate the parasites in the nest and on the young. Sometimes 

 she did this as often as once in four minutes. The male, from 

 the beginning, called the female from the nest regularly for 

 the rest period and fed the young both fresh and chrushed 

 and macerated food. In such a well-ordered nest there was 

 no opportunity for a nestling to starve to death. 



To distinguish the birds in nest two, I tied a cord to the 

 leg of each nestling, and named them No. 1, No. 2, No. 3 and 

 No. 4, in order of their coming to the nest.^ No. 1 and No. 2 



1 found at the same time. Those I numbered according to 

 their weight — No. 1 was the heavier. I tied three cords to 

 the leg of No. 3, but in some way they were all removed on 

 the following day. 



The rapidity with which the young mature is most remark- 

 able. Three of the young measured at birth 1 and 11-16 

 inches, the fourth measured 1 and 9-16 inches, and the young 

 weighed respectively, No. 1, 70 grains ; No. 2, 60 grains ; No. 

 3, 46 and 1-2 grains ; and No. 4. 60 grains. No 2 was the 

 most sleepy bird in the nest. No 1, at the end of the ninth 

 day, was the lightest in weight and had the longest wings, 



2 and 3-16 inches. On the tenth day I succeeded in weigh- 

 ing and measuring but No. 2 and No. 4. (This was the 

 eighth birthday of No. 4.) No. 4 was by far the heaviest and 

 most active bird in the nest, weighing nearly 480 grains. He 

 was not so heavily feathered as the others, his wings were 

 a half inch shorter than No. 2's and his length was one inch 

 less than No. 2's. From birth No. 4 was the most vigorous 

 of all the young. At his first weighing he stood supported 

 on his belly, heels and wings, the latter spread wide apart, 

 held up his head and gave the food reaction all the time he 

 was out of the nest. He fully possessed the power of orien- 

 tation. The increase in weight of this young bird was very 

 marked. He very nearly multiplied his original weight by 



^ I borrowed this device for distingnisliing the nestlings from 

 "At the Sign of the Northern Flicker," by Althea R. Sherman. 

 The Wilson Bulletin. Sept.-Dec. 1910. 



