192 USEFUL BIRDS. 



to the tree trunks. Like the Creeper, it searches every 

 cranny of the bark for insects ; it feeds on wood-boring 

 insects, bark beetles, click beetles, curculios, and the eggs 

 of insects. But it does much more than this, for when it 

 comes to Massachusetts the buds are about to burst, and all 

 through the spring and summer it searches over the limbs, 

 twigs, buds, and leaves, destroying caterpillars, beetles, and 

 bugs that are found on bark and foliage. Now and then it 

 startles a resting moth from a tree trunk, or observes one 

 flying below, and, darting down, catches it in air almost as 

 skilfully as a Flycatcher. Its swiftness and dexterity in fly- 

 catching seem to be derived largely from the impetus of its 

 downward plunge, for, so far as I have observed, it never 

 essays to follow insects that fly by above it. 



The bird is very destructive at times to hairy caterpillars, 

 eating large quantities of them ; and, as it also destroys the 

 pupse and moths of these insects, it exerts considerable in- 

 fluence toward checking the gipsy moth. This Warbler is 

 quite as valuable in the orchard as in the woodland, as it 

 feeds on many orchard pests ; but unfortunately it is not so 

 commonly seen in orchards as in its favorite woods. Its 

 food on those occasions when it descends to the ground is not 

 very well known, but it often picks up cutworm moths that 

 hide there, and Gentry says that it eats earthworms. 



Chestnut-sided Warbler. 



Dendroica pensylvanica. 



Length. — About five and one-half inches. 



Adult Male. — Top of the head yellow ; hack yellow and ashy, blaek-streaked ; 

 ear patch and wing bars, large spots on tail feathers, and under parts, 

 white ; a black patch extends from the lower mandible to and through the 

 eye above, and below to a broad chestnut streak which runs down the side 

 of the body. 



Adult Female. — Somewhat similar, but duller. 



Nest. — Usually in a low bush, lined with fine grasses. 



Eggs. — White, with purplish or reddish brown spots and blotches. 



Season. — May to September. 



This species is a summer resident throughout most of the 

 State, usually appearing here the second week in May. In 

 spring it may be seen gleaning insects in both woods and 

 orchards and in all kinds of vegetation, from low shrubbery 



