This sanitary work continues into the late autumn as long as the caterpillars, the Rook’s favourite food, remain. The Rook may do serious damage during the autumn sowing, especially if it is thin, and sown and harrowed so late that the caterpillars have disappeared, not so much, however, that the field must be ploughed up; at the worst there would remain only one or two unproductive spots, and we know that corn grows in tufts, and if it is not thinned by the Rooks it must be done by the farmer, so that the corn is not choked by its own abundance. When the hard part of winter comes, the flocks of Rooks seek towns and villages, where they spend the nights on the roofs of houses in order to shelter themselves from the icy wind; during the day they steal from the barns and granaries, or, if the opportunity offers, they get at the bundles of straw which they pull about to try and find a stray ear of corn. This much is certain that the principal food of the Rook consists of insects and grubs, which it gets not only from the surface of the earth, but also from beneath it, when the bird sees from the colour of the fading plant that a grub is gnawing at its root. This is the meaning of the uprooted plants; and why one flock after another so often visits the same cornfields. It is a sure sign that the wireworm or some similar pest is busy with its depredations. Here again the work of the Rook is a blessing. There are neighbourhoods where the farmer makes a great fuss about a grain or two of wheat or maize, as if he must be ruined by the damage. I repeat that the bird has earned its few grains by its other work; indeed, without its useful services these grains would probably never have grown. The lesson we learn then is as follows:--The Rook lives principally and preferably on insects, grubs and worms, and so long as these are procurable, it does not look for grain--therefore, the spring sowing should be performed as late as possible, when the insects have developed, and the Rook can find its natural food; in autumn the sowing should be done as early as possible while there are still some insects to be found. The further actions of this bird are protective, for it attacks the gnawing maggots that live in the ground. These facts can be verified by dissection of the bird, when the stomach is often found to be full of wire-worms. None the less researches into the habits of the rook require to be more thoroughly worked out, and this must not be lost sight of. * * * * * I asked a tenant farmer in our own Midlands his views on the subject of Rooks and the following, with some slight editing of my own, was what he sent me. I give it in full as although there may be some repetition of the foregoing statements, it has special interest as coming from one of our English farmers.