This section is from the book "The Balance Of Nature And Modern Conditions Of Cultivation", by George Abbey. Also available from Amazon: The Balance Of Nature And Modern Conditions Of Cultivation.
The rook has been notorious for damage to corn and grain at seed-time for centuries, inasmuch as Henry VIII enacted that " everyone should do his best to destroy rooks, crows, and choughs, upon pain of amerciament, and that every hamlet should provide and maintain crow-nets for ten years, and that the taker of the crows should have after the rate of 2d. per dozen " (about equal to a present value of 4d. per crow). Rooks are still very troublesome on a farm in disturbing and eating corn, maize, and peas, also on newly-planted and mature potatoes. In some cases they are so numerous that many farmers would be glad of an enactment by Edward VII to mulct owners of rookeries with the expenses they are put to in scaring, and with damage to the crops, and also to keep the number of rooks under control by shooting the newly-fledged birds in the respective rookeries to such an extent as make the number at least stationary and not increasing. Good to the farmer is measured by the wireworms, leather-jackets, slugs, snails, worms, woodlice, millipedes, cockchafer and other grubs the rooks consume.
That they devour untold numbers of insect pests is unquestionable, but how is it that great patches of cereals are " under-eaten off" by wireworm in the vicinity of a rookery and the rooks not as eager to bill out the pests as they are the seed-grain? Surely the value of rooks to agriculturists is, in not a few instances, overestimated. The laying-down of much land in recent years to permanent pasture may have something to do with the severer attacks of rooks on crops than formerly, and also account for their depredations, extending in some localities to the pheasant and poultry-rearing grounds, also to their - in fruit-growing districts - making onslaught on strawberries, cherries, gooseberries, and raspberries, especially in dry weather, and sometimes apples and pears. These, however, are local, rather than general depredations, and certainly of recent acquirement. As everybody knows, the rook dearly loves walnuts, and some say cobnuts and filberts. Fruit-growing extension, therefore, demands a decrease of rooks, not the least of their offences being that of frequenting bush fruit grounds where manure is put on in frosty weather preparatory to digging in when the weather permits, and by settling on the bushes, particularly gooseberries, of spreading and pendulous habit, breaking off branches by their weight and ruining recently planted trees.
Trapping rooks is a very old practice, but is now somewhat precluded, as spring-traps are not allowed to be set in the open for dread of catching winged or ground game, and incurring severe penalties. Nevertheless, there is no difficulty in trapping rooks, as they generally alight on the same spot to clear off corn or bill out potatoes, thus enabling the trapper to judge where to set. The traps can be baited, or just set and left to take their chance. We advise the farmer, to conceal each trap and use bait of springing corn on the table for cereal crops, and a portion of potato, preferably a partly rook-eaten one, affixed to the plate, and the trap so covered that only a bit of the bait is visible, for attacks on potato crops. Thus set, the rook will invariably be caught across the head or neck by the jaws of the trap, and dies in a few seconds. On the other head, a rook caught by the leg does not stop struggling until away or dead, consequently the bird may take its departure minus a foot, or much torture be inflicted. Of "catch 'em alive" traps the rook is very wary, and as no scarecrow is so effective as a tethered (by the leg) rook, traps with jaws bound with indiarubber are sometimes employed, so that the leg caught is not easily fractured.
A very ancient plan 1 of making "fools" of rooks is to procure some v-shaped brown paper bags of small size, and smear the inside to the outer edge with birdlime, setting up in the declivities of the land after sowing corn, or setting potatoes, and dropping into each a wireworm or cockchafer grub easily collected in ploughing or digging. The rook sees the bait, pushes its head into the bag, which adhering causes the bird to "caper" and make his fellows merry, or at least raise a great outcry, and leave the crop alone. Of course, the blinded bird should be captured, and either tethered or killed and hung up as a scarecrow. (See further, p. 240.)
1 Mentioned in Practical Trapping, p. 43, L. Upcott Gill, Bazaar Buildings, Drury Lane, London, W.C.