these observations that are recorded here.

Field workers from this Department who have observed the habits of the
principal birds that live among men, have watched them all day and from
one day to another as they fed their little ones, and, to be more
certain of their facts, they have examined the stomachs of hundreds of
birds, both old and young, to learn exactly what each bird had eaten. In
this way they have proved absolutely that many species that are supposed
to eat chickens, or fruit or grain, in reality never touch them, but are
among the farmer's best friends.

Among other things they have learned that while they are feeding their
young, birds are especially valuable on a farm. Baby birds require food
with a large amount of nourishment in it that can be easily digested.
Almost all young birds have soft, tender stomachs, and must be fed on
insects; as they grow older, the stomach or gizzard hardens and is
capable of grinding hard grain or seeds. The amount of food required by
the baby birds is astonishing. At certain stages of their growth they
require more than their own weight in insects. And the young birds are
to be fed just at the season that insects do the most injury to growing
crops of grain and young fruit and vegetables.

Birds vary so much in the kind of food eaten, not only by different
varieties of the same species, but by the same birds at different
seasons, that it is necessary to make a careful study of each bird to
know whether, if he is sometimes caught eating cultivated fruit and
grains, he helps in other ways enough to pay for it.

When insects are unusually abundant, birds eat more than at other times
and confine themselves more strictly to an insect diet, so that at such
times the good they do is particularly valuable.

Birds of prey may do harm in a particular place, because in that region
mice, rabbits and other natural food are scarce, and they are driven to
feed on things that are useful to man, while in places where their
natural food is plentiful the same birds are altogether helpful.

In the same way, birds which naturally eat weed seeds frequently find
these almost altogether lacking where the farms are most carefully
cultivated, but in their place are fields of grain whose seed also
furnishes them desirable food. Is it any wonder, then, that, their
natural food being taken from them, they turn to the cultivated crops?
The fruit eating birds seem always to choose the wild fruit