The Birds’ Calendar 
case of aérial 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 aérial 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 bythe 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 vireo 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 
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