BONG 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 larvae, 

 and eggs ; codling moths with their larvae ; 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. 

 ■ i /. -, . P pillar moth, eaten by Chickadees. 



their eggs torm a large part of 



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 



