SONG BIRDS OF ORCHARD AND WOODLAND. 167 
over half its food consists of insects, and in spring the per- 
centage of insect food often runs up to nearly one hundred. 
Among the pests which it eats are the tent caterpillars and 
their eggs; both species of cankerworm moths, their larve, 
and eggs; codling moths with their larve; the forest tent 
caterpillar ; and the larva, chrys- 
alis, and imago of the gipsy moth 
and brown-tail moth. The birch, 
willow, and apple plant lice or Fig. 50.—Eggs of the tent cater- 
divsie eggs fount a large part of pillar moth, eaten by Chickadees. 
the Chickadee’s food at times. The eggs are eaten mainly in 
autumn and winter, when fixed upon the twigs of trees. Bark 
beetles, so destructive to many species of fruit, shade, and 
forest trees, are a favorite food of the Chickadees. Destruc- 
tive flea beetles also are eaten by them. They frequently 
may be seen tearing open spiders’ “ nests,” and eating the eggs 
or young. At first sight this appears to be a harmful habit, 
as spiders are supposed to be useful; but no doubt much 
destruction of spiders is needed to keep them within normal 
bounds. Let any one go out into the fields some foggy 
summer morning, and note the thousands of “cobwebs” on 
the grass, and he will see that the fields are “full of spiders.” 
One night in September, 1904, I slept on the ground upon 
a hill top in the Concord woods. Early in the night it rained 
a little, and toward morning a river fog rose. At daylight 
the whole country appeared to be covered with spiders’ webs. 
They hung from the trees, every branch was ornamented 
with them, each tuft of pine needles had its web, long 
streamers ran from tree to tree, festoons of spiders’ webs 
hung across the wood roads. The shrubbery, the vines, the 
grass, all were enshrouded in dew-spangled webs. The 
work of a million spiders, ordinarily unnoticed, had become 
visible, as if by magic, in a night. It was plain that the 
woods as well as the fields were spider-ridden. At other 
times flights of migrating spiders are wafted on the air by 
their little balloons or parachutes, rising high and crossing 
ponds and rivers. Such sights as these suggest what might 
occur were not spiders held in check by birds. When we 
consider the vast numbers of spiders and the possibilities 
