Formerly, when the low marshy shores of the Carolinas and some of the more southern States were devoted to rice culture the bobolinks made great havoc both upon the sprouting rice in spring and upon the ripening grain on their return migration in the fall. While the damage is not so great as when this region was the center of rice production, still it amounts to many thousands of dollars annually. As a remedy, an open season on ricebirds was provided in the Coast States from New Jersey to Florida.
In one or another of its geographic races the common crow[44] ([fig. 16]) breeds in great numbers throughout the States east of the Plains and from the Gulf well up into Canada, while in less abundance it is found in California and in the Northwestern States. During the colder months a southern migratory movement brings most of these birds within the borders of the United States, and at about the latitude of Philadelphia and southern Illinois we find them congregating nightly in roosts. Farmers dwelling in the vicinity of such roosts frequently suffer losses to shocked corn.
[44] Corvus brachyrhynchos.
In fact, none of our native birds so much concerns the average farmer of the Eastern States as the common crow. Many of our present criticisms of this bird, as its pulling sprouting corn, feeding on ripening ears, damaging fruits of various kinds, destroying poultry and wild birds, and disseminating diseases of live-stock, were common complaints in the days of the early colonists. Many of the virtues of the crow, now quite generally recognized, also have been matters of record for many years. In recent times, however, scientific study of these problems, including the examination of the stomachs of hundreds of crows secured in every month of the year and under a variety of conditions, has enabled us to render a much fairer verdict than was formerly possible.
The crow is practically omnivorous. During spring and early summer any form of insect life seems to make a desirable item in its diet, and in winter when hard pressed nothing in the animal or vegetable kingdoms which contains a morsel of nutriment is overlooked.
The insect food of the crow, which comprises about a fifth of its yearly sustenance, does much to atone for its misdemeanors. Grasshoppers, May beetles and their larvæ (white grubs), caterpillars, weevils, and wireworms stand out prominently. In 1,340 stomachs of adults examined these highly Injurious forms comprised over 80 per cent of the insect food. Grasshoppers are naturally taken in greatest abundance late in the season. September being the month of largest consumption, when they form about a fifth of the total food. May beetles and white grubs are eaten in every month, but occur most prominently in May. In June caterpillars are a favorite food, and weevils of various kinds are taken in varying quantities throughout summer and fall. About half of the remaining 20 per cent of insect food is composed of beneficial ground beetles, ladybirds, predacious bugs, and parasitic wasps, and related forms, the rest consisting of neutral or injurious forms. Numerous instances are on record where fields badly infested with white grubs or grasshoppers have been favorite resorts of crows, whose voracity has resulted in a material suppression of the pest. When the amount of food required to sustain the individual crow is considered, the work of these birds appears all the more important Single stomachs containing upward of 50 grasshoppers are not uncommon. Thus in its choice of insect food the crow is rendering an important service to the farmer.