Audubon County journal. (Exira, Iowa) 1884-1993, 1921-12-01

thrashers seek their insect prey on or near the
ground; woodpeckers, nuthatches titnlice, and
chickadees closely search the trunks and limbs Of
trees; vireos and warblers the leaves and
probe the flowers; and tlycatchers and swallows
sweep their prey from the air ITSELF Every few
minutes all day long the hungry young must be
fed and that they are well fed their rapid growth
attests. The quantity of insects they and their
parents consume is enormous. Not only orchards
benefit by the good work Of birds, but gardens,
berry patches and powed and newly sown fields
as well. While fields actually grown to tall crops
less freely visited, all crops are helped to some
extent, and practically every farm pest mas Its
bird enemies.
To learn exactly how and to what extent birds
aids to agriculture, horticulture, and forestry
the biological survey has been making scientific
study of their food habits since its establish
ment in 1885. Its Investigations are carried on in
both the field and laboratory. All that can be
learned out of doors by direct observation and by
study of the available food supply is valuable, but
there is way of finding out what brd
eats namely, to look into It's stomach 1t mas
been repeatedly demonstrated that the nature OF
the food and feeding habits of birds Is such that
it is impossible arrive at definite results by d.
rect observation. On the other hand, the eAamina-
ton in the laboratory of the contents OF the stom-
ach gives information that is definite, exact, and
indisputable
From the percentages and the economic value
of the food Items the utility OF a DlfQ can De
closely estimated The biological survey is then
able to recommend how it should be treated
In the United States are found more than 800
distinct kinds Of birds of SO families, of which 70
families are cassed as waterfowl, as shoreb1rds
rs upland game birds, as birds Of prey, and 81
Land birds.
The upland game birds comprise such familiar
groups the quail, grouse, ptarmigan, wild tur-
keys, wild pigeons, and doves The last two while
usually harmless sometimes damage crops
eXten- which requires that they be controlled and
economically they deserve less consideration than
the turkey, quail and grouse. These three kinds
of bids have feeding habits which are helpful to
agriculture. They may be hunted, but their num-
bers should not be reduced below the normal pop
ulation for each type of country
Hswks and owls, though not closely related,
may oe considered together account of the sim
al1sy OF their feeding habits. Feeding chiefly up
on ewing animals smaller than themselves natur-
ally they sometimes prey upon some of the domes--
ticated kinds particularly poultry. This has given
them bad reputation with farmers so long estab-.
listed as to amount to traditional prejudice. Sci
enSifc investigation of their habits shows that only
a .ew species of hawks and only one owl feed chief
ly. or even largely, upon birds, and therefore to
any great extent upon poultry. The birds of prey
regarded chiefly injurious include the sharp
Skinned, Cooper, and duck hawks, the goshawk, and
Il great horned owl. The great horned owl, which,
Ike most of its relatives feeds at night, gets only
poultry that is improperly exposed, and when pre-
vented from doing this It's habits are largely bene-
fetal
The remaining species of hawks and owls, more
than 500 in all, have useful habits. They feed on
great variety of rodents and have tremendous
effect in controlling the numbers of these pests.
..iicr staple food consists for the most part of
1eadOw mice, but it includes also many other de-
stFuctive rodents, such rabbits ground squil-
Ials, prairie dogs pocket gophers, and house rats
and mice.
The barn owl is of the most useful of the
birds of this group. Its food is easily studied by
examination of the pellets made of the hair and
bones Oh IS victims, which accumulate about its
roost. ~ rs barn-owl pellets collected in Wash
ington' D1C., were found the remains OF Ills