22 BIRDS OF SOUTH DAKOTA 
HOW BIRDS WORK FOR US 
To entice the birds about our homes and into our gardens 
by bird houses, baths and food boxes is not only to make them 
our friends but our servants. But for the birds there is no doubt 
that our vegetables, bushes and trees would be destroyed by in- 
sects. Most of our birds are insect eaters, and even seed-eating 
birds feed their young upon insects. All birds are hot-blooded 
creatures and require an enormous amount of food; and, too, 
they seem to be feeding from morning till night. In winter in- 
sects are in very condensed form, usually in the pupa stage, and 
it requires a great many to satisfy a hungry bird, so that every 
bird that searches our tree trunks in winter destroys what would 
be a vast multiplication of insects during the following summer. 
The hosts of insects that the birds destroy in migration 
are beyond all computation, indeed beyond our imagining. 
Whole families of insect eaters, as they pass northward, appear 
in each locality just before or at blossom time—Flycatchers, 
Warblers, Vireos, Kinglets, Swallows and Swifts. They come 
just as most insects are emerging from the pupa state and just 
as others are hatching from the egg. Everywhere the trees are 
alive with hurrying, hungry, feeding birds. Their quick eyes 
search every leaf and examine every bud and blossom. They 
are the savers of our trees and bushes. 
The larger birds that remain with us all summer, such as 
Bluebirds, Orioles, Thrushes, Thrashers, Catbirds, and scores of 
others, live largely on caterpillars. The favorite food of Cuckoos 
is the tent caterpillar, which is so destructive to orchards; and 
a few pairs of Grosbeaks in a potato patch will keep it free from 
the destructive potato bug. The little Wrens will creep under 
every vegetable in the garden looking for worms. Kingbirds 
use the clothesline as a perch and gobble up the passing flies, 
which carry disease from filthy places to infect our food. They 
also destroy robber flies, which kill and eat honey bees. 
Every place in nature has its bird, and few are the birds 
which do not give good account of themselves in rendering 
service for the benefit of man. Even the Hawks and Owls, 
which most boys and hunters regard as legitimate prey, and shoot 
to let lie and rot, are among our most useful birds. There are 
