THE MISSION OF TIIE BIRDS 
*7 
chickadee will sometimes eat more than four hundred eggs of the 
apple plant-louse, while throughout the winter one will destroy an 
immense number ot the eggs of the cankerworm, when these are 
abundant. As soon in spring as the leaves begin to unfold they are 
attacked by the plant-lice that 
have survived the winter as well 
as by many sorts of caterpillars 
and other insects ; the notorious 
cankerworm is one of the worst 
of these. But a host of birds 
come to the rescue of the trees ; 
the aphides are hunted by the 
beautiful little warblers which go 
northward in early May, when 
aphides are thick upon the un- 
folding leaves. The cankerworms 
and other similar leaf-eating cat- 
O 
erpillars form the favorite food 
of many sorts of birds : Robins, 
catbirds, brown thrushes, blue- 
birds, warblers, vireos, cedar- 
birds, sparrows, orioles, and flv- The Kingbird 
catchers all devour them. 
Passing now to the meadows we find a rather specialized condi- 
tion as to insects. The grass plants are low-growing, and have a 
comparatively restricted set of enemies. These, however, are suffi- 
ciently numerous to destroy the crop when not molested by their bird 
enemies. The roots of grasses are commonly attacked by white 
grubs — the destructive larvae of the common May beetles or J line bugs 
— as well as by wireworms — the larvae of the click beetles — and 
plant-lice or aphides which are fostered and cared for by various 
species of ants. The part of the plant just below the soil surface 
is sometimes attacked by meadow maggots — the peculiar larvae of 
the crane-flies and their allies — while various crown and root borers 
affect clover and timothy or herdsgrass. Just above the soil surface 
the fatal work of the cutworms and army worms is done, while still 
higher up the effect of the grasshoppers and chinch-bugs is likely 
to be seen. 
Set over against these meadow pests we have the blackbirds, 
