OF EASTERN PENNSYLVANIA. '2:\7 



sionally been known to take possession of a deserted Crow's 

 nest, and, in one instance, a newly-built nest of the latter, 

 after having driven its rightful occupants awav. But, as a 

 rule, the generality of birds prefer their own workmanship 

 to that of another. In cases where other nests are occupied, 

 it is mainly done b\ young birds, or those of indolent habits. 

 The time required for the construction of a nest, seldom 

 exceeds three days. It is the work of both sexes, who labor 

 most vigorously during' a portion of each day, chiefly in the 

 morning, until the fabric is completed. The male-bird 

 mostly provides the materials which he procures close-by, 

 while the female busies herself with their proper adjust- 

 ment ; sometimes, however, assisting her partner in his 

 more burdensome occupation. 



Oviposition follows cjosely upon the completion of the 

 nest. In many instances, the eggs that constitute a comple- 

 ment, are deposited either on successive, or alternate days. 

 before incubation is assumed. Sometimes the female com- 

 mences to sit after the deposition of two eggs ; the residue 

 being laid at somewhat irregular intervals during the 

 incubating process. It therefore happens that the same 

 nest often contains both young birds and eggs in divers 

 stages of development. The female does not assume the 

 sole responsibility, but shares it with her mate, who per- 

 forms his portion of the task with alacrity. When the 

 former, who is the first to occupy the nest, is ready to retire 

 tor a brief season of relaxation and pleasure, her intentions 

 are indicated by a peculiar sound, which is responded to by 

 the male, who is in the immediate vicinity awaiting with 

 expectancy the anticipated summons. From three to four 

 hours is the limit. While one is sitting, the other after hav- 

 ing attended to his appetitive demands, repairs to a spot in 

 full view of the nest, over which he exercises the closest 

 surveillance ; punishing with severity other birds should 

 they dare to trespass upon his territory. Even human 

 beings when venturing too near, are sometimes made to 



