SOME COMMON BIRDS OF NORTH AMERICA 373 



post, or on the ground, but in the evening it mounts into the 

 air after its insect prey. The two eggs are laid on the bare 

 ground, usually on a hillside or in an open field; often they are 

 deposited on the gravel roofs of city buildings. 



FIG. 255. - - A family of bluebirds. Three of the young are on the stick 

 near the father bird. The mother bird is on top of the fence post. (Photo. 

 by Hegner.) 



The humming birds, which are confined to the New World, 

 have been appropriately called feathered gems, or, according 

 to Audubon, " glittering fragments of the rainbow." Only one 

 species, the ruby-throated humming bird, is found east of the 

 Mississippi River. This beautiful little bird is only three and 

 three-quarters inches in length. It hovers before flowers, from 

 which it obtains nectar, small insects, and spiders. The nest, 

 which is saddled on the limb of a tree, is made of plant down and 



