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to illustrate this habit was not available at Marshall Hall, but the diagrams here given (figs. 17 and 18), based on results obtained elsewhere," will serve to show it. By the time the young are ready to leave the nest, however, they are fed to a large extent on either grain or fruit, according to locality. In the Middle West they take grain and in the East generally fruit. Both crows and crow black

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FIG. 17.-Diagram showing proportions of food of American crow ( Corvus americanus), young and adult.

birds do great service by feeding to their young not only cutworms and grasshoppers, but also large numbers of weevils and May-beetles.

GENERAL REMARKS.

Consumption of caterpillars and grasshoppers is the largest benefit derived from the presence of nestlings on the farm. The parent birds

@ Most of the stomachs of young and adult crows used in the investigation on which the results shown in the diagram are based were obtained at Sandy Spring, Md.; and most of those of young and adult crow blackbirds came from Onaga, Kans,

are rare.

hunt out these insects when they are not abundant and even when they At the time of the foregoing observations of orchard orioles, house wrens, and grasshopper sparrows, caterpillars and grasshoppers were comparatively scarce; yet the parent birds, though they chose insects for their own eating from more abundant species, hunted far and wide for these rare ones to feed their young. At Marshall Hall

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FIG. 18.-Diagram showing proportions of food of crow blackbird (Quiscalus quiscula æneus), young

and adult.

the protection and encouragement of birds at nesting time is of prime importance. Adults of the most numerous species on the farm are either highly frugivorous or highly granivorous, hence the insectivorous habits of nestlings help considerably to establish the beneficent relation of birds to the farm economy.

7222-No. 17-02- 4

III. VERTEBRATE FOOD.

POULTRY AND GAME.

Crows. Certain species of the larger birds were found to take vertebrate food. Crows and some of the hawks and owls destroyed useful small birds and also game and poultry. On the Hungerford farm crows were observed killing newly-hatched turkeys, and on the Bryan farm they were not uncommonly seen carrying off little chickens. The most serious offense against the poultry interest, however, was the habitual stealing of eggs. During April, 1900, a crow came every day and robbed a hen's nest in the side of a hay rick at a little distance from buildings. Often he would be seen waiting on a fence near by until the hen announced that the egg had been laid, when he would dash down and make off with his booty. Such depredations could be avoided by furnishing the hens with such facilities that they would no longer lay in exposed situations. As it is, incessant war upon the crow is necessary to prevent heavy loss to poultry on this farm. Game birds also suffer. On May 15, 1900, a crow was caught on the forested slope beyond the swamp (Pl. VII, fig. 2) in the act of pillaging the nest of a ruffed grouse. Crows also despoiled the nest of a bobwhite, a species which probably suffers oftener than the ruffed grouse.

Eagle. The bald eagles that are frequently seen at Marshall Hall do not disdain to pick up a little game now and then. Early in March, 1897, a crippled scaup duck was seen in the river a hundred yards from the house chased by an eagle and diving every time its pursuer swooped down on it. When the quarry was almost tired out the eagle was shot, and fell into the river with a broken wing, but it had sufficient strength left to lacerate a pointer that attempted to retrieve it. On November 15, 1900, an eagle was seen flying over the house gripping in its talons a live coot, which turned its head rapidly from side to side in its struggles to escape. During the hunting season eagles get a good part of their food by picking up wounded ducks. They also prey on domesticated ducks. In the first week of August, 1896, they carried off several ducklings that went down to the swamp. The royal brigands relish chicken, and in the nest of one pair that came to the farm was the carcass of a recently killed Plymouth Rock hen.

Cooper Hawk. With the exception of the English sparrow, the Cooper hawk (fig. 19) probably does the least good and the most harm of all the birds of the farm, for it subsists almost entirely on wild birds and poultry. It very frequently steals little chickens, and constantly preys on the bobwhite and useful insectivorous or seed-eating small birds. During November, 1900, the bobwhites were so persecuted that they were seldom found far from cover. In one instance a hawk was seen to swoop to the ground and rise with a victim, the

identity of which was afterwards made sure by the discovery of the feathers of a cock bobwhite on the spot where the hawk had struck. Sharpshinned Hawk. The sharpshinned hawk, congener of the Cooper hawk, is also a harmful species. It was frequently observed pursuing native sparrows, and on November 15, 1900, was seen tearing a mockingbird to pieces. The smaller birds suffer most in autumn. On the 15th of November, 1899, I was observing a score of cardinals, juncos, white-throated sparrows, fox sparrows, and song sparrows

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that were eating ragweed seed in wheat stubble by the negro cabin. Suddenly the whole flock sprang into the air and flew straight toward me and into the bushes behind me, twittering with fright. Their swiftness just saved them from a sharpshinned hawk, which swooped and struck the ground where they had been feeding. It was two hours before they dared to leave their shelter and feed again on weed seeds of the stubble-field. These two species of hawks patrol the farm

so vigilantly in autumn and winter that birds which eat weed seed are kept in constant terror, and are unable to do all the good they might accomplish were it not for their tireless enemies. Owing to the depredations of these two hawks, all hawks without distinction have been relentlessly persecuted by man, although very few are actually detrimental to agriculture.

Great Horned Owl.-Only one of the several species of owls occurring at Marshall Hall is harmful, namely, the great horned owl (fig. 20).

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It occasionally makes inroads on poultry that is not housed. December, 1897, a great horned owl carried off a full-grown hen from her roost in a tree beside the negro cabin, and on five of the first ten nights of May one came and took hens from the cedar trees behind the house. On the night of the sixth visit a steel trap baited with a hen secured the robber. A year seldom passes without losses from this fierce and powerful bird of prey.

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