What Birds Do for Us 



insects deposit their eggs that their young may have 

 the freshest, tenderest leaves to feed upon. Some 

 few warblers, in the great family, confine their labors 

 to the ground and undergrowth, it is true, and a few 

 others pick their living out of the trunks of trees, 

 but they are the exceptions which prove the rule. 

 Countless millions of larvae, plant lice, ants, canker- 

 worms, leaf-hoppers, flies, and the smaller cater- 



Parasites on Caterpillar host. What the Vireo sees under a leaf 



pillars go to supply the tireless energy of these 

 charming little visitors each time they migrate 

 through our neighborhood. Generally speaking, 

 the vireos, or greenlets, are less nervous and more 

 deliberate and thorough in their search than the 

 warblers. Cocking their heads to one side, they 

 scrutinize the under half of the leaves where insects 

 have sought protection from just such sharp eyes as 

 theirs, as well from rain and sun. After a warbler 



175 



