Nesting Behavior of the Yellow Warbler. 57 



After blue left the nest on July 10, the female seemed to 

 take care of it, for many times she was seen to approach with 

 food, but would dart into the weeds near by, and soon fly out 

 with bill empty. She would also remain away from the nest 

 for rather long periods at this time. For example, a period 

 of twenty minutes elapsed between visits No. 2148 and No. 

 2149, and fourteen minutes between visits No. 2442 and 

 No. 2443. 



When the observations commenced the parent birds were 

 feeding the young large food, such as insects and green 

 worms. As described elsewhere the writer was present when 

 the fourth Qgg hatched and is able to state that the food of 

 this bird was not at all different from that which was being 

 given to the rest of the nestlings, viz., green worms, grass- 

 hoppers, and other insects. At no time while the nest was 

 under observation did the parents feed by regurgitation. It 

 might be said that on visits Nos. 138, 440, 745, 769, and 798, 

 one or other of the parents came to the nest with beak empty, 

 so far as could be discerned. This parent then thrust its bill 

 into the mouth and throat of one of the young birds, and 

 then repeated the act on another. Then again on visits Nos. 

 751, 1059, and 1880, after the parent bird fed one of the 

 nestlings, it put its apparently empty bill in the mouth of one 

 of the other young. This behavior is not understood, but 

 is not regarded as explainable on the assumption of regurgi- 

 tative feeding, for the reason that it was long after hatching, 

 and so irregular and infrequent. 



Brooding. 

 Brooding was carried on entirely by the female, with one 

 possible exception. On July 3 the observer, who was in the 

 blind it the time, recorded that the male brooded for seven 

 minutes. Since this is the only instance where such beha- 

 vior on the part of the male was noted by any one, and be- 

 cause the writer observed on two occasions the male perched 

 on the edge of the nest inspecting the young, once for a 

 period of four minutes, it seems doubtful if the observer 



