Owls carried on by the United States Department of Agriculture go to
show that these birds, with but few exceptions, are the farmer's
friends rather than his enemies. It appears that the good which they
accomplish in the way of destroying mice, gophers, rabbits and other
small mammals along with great quantities of noxious insects far
exceeds the possible harm they do by the occasional destruction of
poultry and other birds. A critical examination of the actual contents
of about twenty-seven hundred stomachs of these birds showed that only
six of the seventy-three species found in the United States are
injurious. Three of these are so rare that they need not be
considered. Of the remaining three the Fish Hawk is only indirectly
injurious: hence but two remain to be considered, viz., the
Sharp-shinned and Cooper's Hawks. "Omitting the six species that feed
largely on poultry and game, 2,212 stomachs were examined, of which
56 per cent contained mice and other small mammals, 27 per cent insects,
and only 3½ per cent poultry and game birds."

The food habits of both the Turkey Vulture and Carrion Crow, or Black
Vulture, are of such a nature that the destruction of these birds
should be prohibited. In fact, in many of the states this is done by
law. They live almost exclusively upon carrion or decomposing animal
matter, and in this manner aid in the prevention of diseases that
might result from the presence of such filth. They may, however, be
the cause of indirectly spreading hog cholera where animals that have
died from this disease are left unburied or unburned.

The Cuckoos are among the few birds that habitually feed upon hairy
caterpillars, such as the various "tent-making" species. They also
destroy large numbers of other caterpillars, and do not object to
beetles and other insects which they find among the foliage of trees.