Some Records of the Feeding of Nestlings. 67 



2. During this time the parents fed the nestlings 2373 

 times. 



3. The incubation period for Dendroica cestiva is eleven 

 days. 



4. The egg shells are disposed of by being devoured by 

 the parents. 



5. This species does not feed its young by regurgitation 

 at any period. 



6. Brooding is carried on only by the female. 



7. Intensity of brooding is due to a complexity of fac- 

 tors, including nest location. 



8. The brooding instinct can be modified by artificial en- 

 vironment. 



9. During the first half of the nestling period, the ex- 

 creta sac is usually devoured, and carried away during the 

 latter half. 



10. The excreta sac is either dropped to the ground or 

 deposited on the limb of a tree. 



11. The parent birds have a stereotyped approach to the 

 nest. 



Sioux City, lozva. 



SOME RECORDS OF THE FEEDING OF NESTLINGS. 



BY LYNDS JONES. 



During the summer of 1912 two students made a number 

 of studies of the feeding of nestlings, summaries of which I 

 herewith present. These studies were made without the aid 

 of a blind, because it was found possible to approach within 

 a few feet of the nests without disturbing the parent birds 

 in their feeding activities. It was also' found that the sex of 

 the birds could be determined positively, after noting each 

 bird for the first few hours. This was done by noting the 

 individualities of the two birds, and by the frequent singing 

 of the male, either just before or just after he delivered the 

 food. , ■ ,' :' : ^ I ■ ' - .ii -■'■""1 



