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 asa 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 
pupz 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; back yellow and ashy, black-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 
