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 oft' 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 



WATCH 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. 



