OF EASTERN PENNSYLVANIA. 335 



sociality existed. Upon the males mainly devolve 

 the responsible duty of incubation. During this 

 period the male bird is so persistent and en- 

 thusiastic singer, even while in the presence of his 

 partner, as to betray his nest by the power of his 

 song. Whilst sitting he is so apparently utterly 

 oblivious to the task he is performing, as to at- 

 tract by his melody, intruders to his nest. 



The eggs are usually a light verdigris-green or 

 greenish-white, and are marked with ferruginous 

 spots, more or less diffused over their entire sur- 

 face. They resemble very closely those of the 

 Tanagers', but are generally larger. The average 

 length is .94 of an inch and breadth .68. 



Cyanospiza cyanea, Baird. 



The Indigo Bird is quite abundant in Eastern 

 Pennsylvania, where it arrives usually about the 

 1 2th of May. It prefers the borders of thickets, 

 and fields overgrown with brier-bushes. Although 

 an uncommon visitor about houses, we have never 

 known it to nidificate in such places. 



Though partial to sequestered situations during 

 the breeding-period, it would seem that this 

 species is shy and suspicious; but we are convinced 

 that it manifests but ordinary timidity during the 

 continuance of its stay. The localities which it 

 frequents, doubtless, possess advantages which 

 others do not present. 



Arriving at a time when insect-life is. already 

 abundant and steadily on the increase, a plentiful 



