104 USEFUL BIRDS. 
winter the smaller wood birds that remain in the north must 
subsist largely on the hibernating eggs of insects, for many 
insects pass the colder months in the egg; the bird that eats 
these eggs can destroy at least a hundred times as many 
insects in this minute, embry- 
onic form as it could in the 
summer, after the caterpillars 
had hatched and grown toward 
maturity. The Jays, Titmice, 
Nuthatches, and Woodpeckers, 
which remain through the win- 
ter in the northern woods, give 
months more of service to our 
trees than do the majority of 
birds that come here as sum- 
mer residents or migrants only. 
These all-the-year-round birds, 
with the Creepers and Kinglets, 
Fig. 34.— Winter tree guards, a are the most valuable guardians 
peg eee of the wood. Millions upon 
millions of insects and their eggs are destroyed by them 
during the long winter months. In this work they are 
assisted to some extent by certain of the winter Finches 
and Sparrows. 
Birds guard All Parts of the Tree. — Even insects which 
feed upon the roots are dug out of the ground by birds, or 
attacked by these feathered enemies whenever they appear 
above the surface. Sparrows, Thrushes, and Towhees search 
among the dead leaves for caterpillars which drop from the 
trees and crawl on the ground, and for those which pupate 
among the litter of the forest floor. Woodpeckers, tapping 
the trunks, find and bring forth injurious ants, bark beetles, 
and wood-boring insects. Creepers, Kinglets, Titmice, and 
Nuthatches search the bark and cavities of the trunk and 
limbs for insects’ eggs, scale insects, bark lice, borers, bark 
beetles, and other insects which hide there. Jays, Warblers, 
Tanagers, Wrens, Titmice, Vireos, Cuckoos, and other tree- 
loving birds pry about among the leaves and branches in 
search of caterpillars of all sorts. Even the hidden leaf- 
