OF EASTERN PENNSYLVANIA. 209 



which they had been placed, as if to seek further 

 favors. This they did several times. In view of 

 these' facts the strongest arguments would be re- 

 quired to convince us that this was not an exercise 

 of reason of a simple order. 



Nest-building usually requires a period of six 

 days, and is the joint labor of the sexes; the male 

 is chiefly occupied in fetching the materials, while 

 the duty of his partner is the adjustment of them 

 to their proper places; when disengaged from 

 such services, she willingly assists her mate. 



Oviposition commences on the da,y following 

 the completion of the nest, and continues for five 

 days ; proceeding at the rate of one egg per day. 

 Then follows the next day, the essential labor of 

 incubation, which, as far as we have been able to 

 determine, is the exclusive duty of the female, for 

 a period varying from 13 to 14 days. Whilst his 

 ma.te is thus engaged, the male acts in the capacity 

 .of purveyor. When not thus employed, he stations 

 himself close by the nest and keeps the most 

 vigilant guard. The approach of enemies is sig- 

 nalled by a low note. Unlike many other species 

 which we have described, he lacks the courage to 

 defend his nest and partner; but slinks silently 

 away and becomes a passive observer of what fol- 

 lows. The female taking the hint follows his ex- 

 ample. 



It now feeds upon what berries it can procure, 

 but more exclusively upon diptera, aphides and 

 the larvae of various species of lepidoptera. The 



N 



