550 BULLETIN 2 03, UNITED STATES NATIONAL MUSEUM 



interpretation may be correct, but it is rare for birds to exhibit such 

 intelligence or to detect the sequence in which the young are fed. 



By the eighth day the feathers have proceeded in the unsheathing 

 process to such an extent that the young present a smooth and pleas- 

 ing contour. A few tufts of down, however, still cling to the ends of 

 some of the contour feathers. Now that the young have a substantial 

 protective covering and have acquired a temperature control, con- 

 tinuous brooding is not essential, but during extreme weather condi- 

 tions, such as a cold rain or when the nest is exposed to the direct rays 

 of the sun, the female protects the young by shielding them with her 

 half-spread wings. 



On the ninth da.y the young are ready to leave the nest and the 

 least disturbance at the nest is a signal for them to leave. Under nor- 

 mal conditions they remain at the nest until the tenth day. 



On June 10, 1945, I flushed a ju venal northern yellowthroat from 

 the tall grass on Cone Island, off the coast of Maine. It flew but a 

 few yards and alighted on a limb of a small dead shrub. The bird 

 then allowed me to approach very near and exhibited not the least 

 fear of my presence or that of the three other observers who stood 

 nearby staring at the little creature. When we continued on our way 

 the bird persisted in following us alighting again and again within 

 a few feet of us. The youngster followed us in this manner for nearly 

 a mile, until finally it joined company with an adult male, possibly 

 its parent, and together they disappeared in the dense vegetation. 



A. D. DuBois sends notes of his observations of a northern yellow- 

 throat caring for a young cowbird and of its own young at Lincoln, 

 Illinois, on June 21, 1913 : "Found a female yellowthroat caring for 

 a young cowbird which could fly very well and was about twice her 

 own size. The cowbird flew to a bush near me. Its foster mother 

 was nearby with food in her bill but she became agitated at my pres- 

 ence and flitted about, chirping. I suddenly clapped my hand over 

 the young cowbird and thus caught it. The cowbird cried out with 

 its squeaky voice and both male and female yellowthroats were im- 

 mediately on the scene of the disturbance, fully as much concerned 

 as though this young rascal were their own flesh and blood. The 

 male, particularly, spread and fluttered his wings in a little bush 

 10 or 15 feet away, exhibiting great excitement, while the female 

 chirped nervously from beneath a bush on the other side. They did 

 not flutter along the ground as many birds do but remained in the 

 weeds and bushes while doing all in their power to attract my atten- 

 tion. Sometimes the male held up his wings in a very pretty fashion. 

 When I released the young cowbird it flew probably 100 feet, the 

 foster mother following after it. 



