4 COMMON BIRDS OF TOWN AND COUNTRY 
at least till the time of migration. Shal- 
low trays of wood or metal admirably 
serve the purpose, especially as birds de- 
light to bathe in them. 
BIRDS SHOULD EVERYWHERE BE PROTECTED 
By supplying artificial nest-boxes the 
number of birds may be increased around 
farms and orchards where their services 
are most needed. The average farmer’s 
boy, if provided with a few tools, is quite 
equal to the task of making acceptable 
boxes for martins, swallows, bluebirds, 
wrens, woodpeckers, and other species, 
which are far from fastidious as to the 
appearance of the box intended for their 
occupancy. 
Entomologists have estimated that in- 
sects yearly cause a loss of upward of 
$700,000,000 to the agricultural interests 
of the United States. Were it not for our 
birds the loss would be very much greater, 
and, indeed, it is believed that without the 
aid of our feathered friends successful 
agriculture would be impossible. 
A knowledge of the birds that protect 
his crops is, therefore, as important to 
the farmer as a knowledge of the insect 
pests that destroy them. Such informa- 
tion is the more needful because the rela- 
tion of birds to man’s interests is ex- 
tremely complex. 
Thus, while it may be said that most of 
our birds are useful, there are only a few 
of them that are always and everywhere 
useful and that never do harm. Insec- 
tivorous birds, for instance, destroy, 
along with a vast number of harmful in- 
sects, some parasitic and predatory kinds. 
These latter are among Nature’s most 
effective agents for keeping destructive 
insects in check. To the extent, then, 
that birds destroy useful parasitic insects, 
they are harmful; but, taking the year 
round, the good they do by the destruc- 
tion of insects injurious to man’s interests 
far outweighs the little harm they do. 
It may be said, too, that of the birds 
usually classed as noxious there are very 
few that do not possess redeeming traits. 
Thus the crow is mischievous in spring 
and sorely taxes the farmer’s patience 
and ingenuity to prevent him from pull- 
ing up the newly planted corn. More- 
over, the crow destroys the eggs and 
young of useful insectivorous and game 
birds; but, on the other hand, he eats 
many insects, especially white grubs and 
cut-worms, and destroys many meadow 
mice; so that in much (although not all) 
of the region he inhabits the crow must 
be considered to be more useful than 
harmful. 
THEIR WINGS ENABLE BIRDS TO ACT 
EFFICIENTLY AS POLICEMEN 
Most of the hawks and owls even— 
birds that have received so bad a name 
that the farmer’s boy and the sportsman 
are ever on the alert to kill them—are 
very useful because they destroy vast 
numbers of insects and harmful rodents. 
Birds occupy a unique position among 
the enemies of insects, since their powers 
of flight enable them at short notice to 
gather at points where there are abnormal 
insect outbreaks. An unusual abundance 
of grasshoppers, for instance, in a given 
locality soon attracts the birds from a 
wide area, and as a rule their visits cease 
only when there are no grasshoppers left. 
So also a marked increase in the number 
of small rodents in a given neighborhood 
speedily attracts the attention of hawks 
and owls, which, by reason of their vora- 
cious appetites, soon produce a marked 
diminution of the swarming foe. 
One of the most useful groups of na- 
tive birds is the sparrow family. While 
some of the tribe wear gay suits of many 
hues, most of the sparrows are clad in 
modest brown tints, and as they spend 
much of the time in grass and weeds are 
commonly overlooked. Unobtrusive as 
they are, they lay the farmer under a 
heavy debt of gratitude by their food 
habits, since their chosen fare consists 
largely of the seeds of weeds. Selecting 
a typical member of the group, the tree 
sparrow, for instance, one-fourth ounce 
of weed seed per day is a conservative 
estimate of the food of an adult. 
On this basis, in a large agricultural 
State like Iowa tree sparrows annually 
eat approximately 875 tons of weed 
seeds. Only the farmer, upon whose 
shoulders falls the heavy burden of free- 
ing his land of noxious weeds, can realize 
what this vast consumption of weed seeds 
means in the saving and cost of labor. 
