Page:The Zoologist, 1st series, vol 1 (1843).djvu/396

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368
Birds.

gate in our turnip-fields, and with their strong bills dig holes into the valuable tubers, which do not long survive this rude treatment; the Swedish variety seems to be their favourite. The wild oat (Avena fatua), a most obnoxious weed, abounds to an injurious extent in some parts; it ripens and casts its seeds before the sickle is put to the crop, and these lie in the ground till circumstances are favourable to their germination, and the most careful tillage fails to eradicate them. 1 am credibly informed that rooks have at times seriously injured fields of young grass, by stocking up the red clover plants to get at these oats; but I have often seen them thus engaged in fields where the wild oat was unknown; perhaps they were searching for larvæ. Rooks are much addicted to pulling up all the cultivated Cerealia and fieldbeans, shortly after their appearance above ground. I once observed them do signal injury to a field of wheat, by pulling up the sickly plants, wdrich were suffering from the dreaded ravages of the Chlorops pumilionis, or some allied species. On examining the plants pulled up, I found the larva untouched in its narrow cell, near the neck: I suspect that the rooks expected to have found noble game at the root of the plant. Though the larva is almost sure to perish when its nidus is thus exposed to the vicissitudes of the seasons, still I would gladly dispense with the officious interference of the rook; for though the main stalk of the plant always perishes, yet, under favourable circumstances, fresh plumules spring from the neck of the plant, which in due season clothe the ravaged portions of our fields with a vigorous vegetation. When clearing off the last of the turnip-crop in March and April, an immense number of larvae are turned up by the plough. A large fleshy caterpillar, which often inflicts severe injuries on the bulbs of this valuable crop, and which my kind friend Mr. A. White, of the British Museum, informs me belongs to a species of Agrotis, a root-eating genus of moths, affords them a dainty and abundant fare. At this season the rook renders the farmer valuable service, in searching the oat-fields and overturning clods and bits of turf in quest of wireworms, the larvæ of craneflies (Tipulidæ), &c.: and for such labours we cannot feel too grateful. His attacks on the potato-field rouse the whole rural population in arms against him, as all, or at least most, of the farm servants in the county get a piece of potato-ground in part payment of wages: and many maledictions are heaped on his head by the labourer, who has children to provide for as well as the rook, which, once fairly bent on plundering a field, will never cease its attacks till driven away by the gun or rattle of the watchman, who, if he intermit his vigilance for a time, is sure to have his