16 BIRDS THROUGH AN OPERA-GLASS. 
dry grasses and similar materials. The eggs, 
from four to seven in number, are generally plain 
pale greenish blue, but occasionally white. 
Sitting on a fence at a little distance the young 
birds look almost black, but as they fly off you 
catch a tinge of blue on their wings and tails. 
Their mother is more like her husband, but, as 
with most lady birds, her tints are subdued — 
doubtless the result of “adaptation,” as bright 
colors on the back of the brooding mother would 
attract danger. 
We have two reasons for gratitude to the blue- 
bird. It comes home early in the spring, and is 
among the last to leave in the fall, its sweet note 
trembling on the air when the “ bare branches of 
the trees are rattling in the wind.” 
IV. 
CHIMNEY SWIFT; CHIMNEY “SWALLOW.” 
WartcH a chimney swift as he comes near you, 
rowing through the air first with one wing and 
then the other, or else cruising along with sails 
set. Look at him carefully and you will see that 
he is not a swallow, although he often goes by 
that name. He looks much more like a bat. His 
outlines are so clear cut and angular that he could 
be reduced, roughly, to two triangles, their com- 
mon base cutting his body vertically in halves. 
ae 
