3O2 LIFE-HISTORIES OF BIRDS 



well secured laterally by enveloping leaves and 

 twigs, it is slightly inclined in position, and bears 

 a circular aperture sufficiently capacious for the 

 passage of the bird's body. This opening is 

 located in the superior third of the nest. When 

 the bird is in position its bill projects through the 

 aperture. It is obvious that the position of the 

 nest is designed by its authors to afford the re- 

 quisite protection to the female and young during 

 inclement weather; this inclination causing one 

 side to serve as a roof. The angle which the nest 

 makes with the supporting surfaces is about 45. 



One of the most curious exceptions to the 

 normal type of nests, was noticed by us in the 

 spring of 1870, in Northumberland Co., Pa. This 

 nest was located upon a small bush, at a slight 

 elevation above the ground. It is composed, ex- 

 ternally, of small branchlets of Draba with seed- 

 vessels attached, a few rootlets, and is lined with 

 white horse-hairs. It has a diameter of nearly 

 four inches, and a thickness of three and a half 

 inches. The diameter of the cavity at the margin 

 is two inches, and the depth nearly two inches. 

 It is a magnificent structure, thickly and firmly 

 woven, and hemispherical in contour. 



The differences just noticed in nidification, are 

 doubtless due to the skill of the architects. As 

 remarked previously, birds like men, have their 

 skilful as well as unskilful mechanics. The latter 

 embrace besides the talentless, the immature and 

 inexperienced. 



