NORTHERN AND MARYLAND YELLOWTHROATS 549 



all of the brooding, but by the fourth day she spent less time at the 

 nest and took more excursions in search of food. 



The young usually emit a fecal sac after they are fed, and this is 

 immediately seized by the parent that chances to be present. During 

 the first few days the fecal sacs are usually eaten, but in later nest life 

 they are more often carried away some distance from the nest and 

 dropped. I have seen the female eagerly keep watch for fully 5 min- 

 utes in anticipation of the fecal sac, even stimulating the youngsters 

 with the tip of her bill to make them respond. The birds also removed 

 all other foreign material such as a pellet of gum, small wads of paper, 

 or rolled-up leaves purposely dropped into the nest as an experiment. 

 The eggshells were removed at the time of hatching by the female. 

 Nelle E. Shaver (1918) gives an interesting account of the removal 

 of an addled egg as follows : 



The nestlings had crept to one side of the nest to escape the rays of the sun, so 

 that the addled egg remained alone and in plain view. The male Yellow-throat 

 came first to the nest with food. Seeing the addled egg he picked it up between 

 the mandibles and carried it away, without breaking it and with no slips or 

 imsuccessful trials. The bird, carrying the egg, disappeared in the foliage of 

 the trees at a distance of about twenty-five feet from the nest. It is possible that 

 the ridge formed by the shell fragment may have furnished a "grip" by which 

 the egg was firmly held in the mandibles. On the other hand, the mandibles are 

 capable of opening to a surprising degree, and the whole behavior of the bird 

 in this act seemed to proceed without uncertainty or experimentation. 



This behavior is probably unusual, as in nests that I have had under 

 observation the infertile egg remained until after the young normally 

 left the nest. 



By the fifth day the papillae of the larger feathers are bursting 

 from their tips and this process is considerably advanced by the fol- 

 lowing day. At times the adult birds peck at the feathers apparently 

 to facilitate the process of unsheathing. On the sixth day the young 

 exhibit evidence of fear when a human observer examines the nest. 

 The food delivered at this time consists of many adult insects such as 

 small moths, spiders, beetles, and grasshoppers. A. C. Redfield (1911) 

 made a unique observation concerning the order in which the young 

 are fed, as follows : "On one occasion the male fed two of the young. 

 Before he had left, the female arrived with an irsect. He held his 

 bill toward her as though wishing to take the food from her. Not 

 heeding him she proceeded to feed the young one last favored by the 

 male. Quickly her mate removed the food from the young one's mouth 

 and thrust it into the bill of the third young one, which had received 

 nothing. This would make it appear that the parent birds do actually 

 keep account of which young they have last fed." Mr. Kedfield's 



981873—53 36 



