The attempts occasionally made by man to interfere with the balance of powers as arranged and sustained by Nature, are seldom successful. An extensive experiment appears to have been made in some of the agricultural districts on the Continent, the result of which has been the opinion that farmers do wrong in destroying rooks, jays, sparrows, and, indeed, birds in general on their farms, particularly where there are orchards. In our own country, particularly on some very large farms in Devonshire, the proprietors determined, a few summers ago, to try the result of offering a great reward for heads of rooks; but the issue proved destructive to the farms, for nearly the whole of the crops failed for three successive years, and they have since been forced to import rooks and other birds to stock their farms with. A similar experiment was made a few years ago in a northern county, particularly in reference to rooks, but with no better success; the farmers were obliged to reinstate the rooks to save their crops. But as, perhaps, the most interesting account of the value of rooks will be found in an extract from the _Magazine of Natural History_, vol. vi. p. 142, we cannot do better than transcribe it:— “In the neighbourhood of my native place (in the county of York),” says the writer, Mr. T. Clithero, “is a rookery belonging to W. Vavasour, Esq., of Weston, in Wharfdale, in which it is estimated that there are 10,000 rooks; that 1 lb. of food a week is a very moderate allowance for each bird, and that nine-tenths of their food consists of worms, insects, and their larvæ; for, although they do considerable damage to the fields for a few weeks in seed-time, and a few weeks in harvest, particularly in backward seasons, yet a very large proportion of their food, even at these seasons, consists of insects and worms, which (if we except a few acorns and walnuts in autumn) compose at all other times the whole of their subsistence. Here, then, if my data be correct, there is the enormous quantity of 468,000 lb., or 209 tons, of worms, insects, and their larvæ, destroyed by the rooks of a single rookery in one year. To everyone who knows how very destructive to vegetation are the larvæ of the tribes of insects, as well as worms, fed upon by rooks, some slight idea may be formed of the devastation which rooks are the means of preventing.” Let this, then, suffice for the rooks; but starlings, wagtails, larks, and other birds, are also helpmates to the farmer; and therefore the wanton destruction of these will certainly bring, nay, has already brought, a great amount of trouble upon the cultivator of the soil.