The Birds' Calendar 



case of aerial birds the altitude of the nest is 

 about in the plane of their average flight, and 

 while the little vesper sparrow selects a tussock 

 of grass in which to build, the grand and lone- 

 ly mountain is the foundation of the eagle's 

 home. Among aerial birds, too, there is an 

 irregular parallelism between the size of the 

 bird and the height of the nest — many war- 

 blers and sparrows choosing the ground, or 

 a slight elevation, the larger finches, crows, 

 hawks, and eagles going successively higher 

 and higher. 



A constant thought of a bird is, *' Many are 

 they that rise up against me," and safety is 

 commonly the first consideration in the loca- 

 tion of nests. In this they are materially as- 

 sisted by the generally inconspicuous colors of 

 the female, and among the sparrows, which 

 mostly nest on the ground, so that the eggs 

 and young are especially exposed to the depre- 

 dations of other animals, by the neutral color- 

 ing of both sexes. The Maryland yellow- 

 throat finds security in the seclusion of low 

 bushes, the red-eyed virco in the manifest ex- 

 posure of the tip-end of a branch, in a "priv- 

 acy of light," and the bobolink concludes to 

 run his chances by camping down on the open 



314 



