2nd. The insects have by no means been destroyed by the birds. Ask of the agriculturists what species has disappeared. Let them search ever so keenly, and they will not find that a solitary species has diminished. On the contrary, in the years referred to we have seen them increase, and grow, and flourish, and nothing prevents them from making war at their pleasure on the invisible animalcules.
Not an insect-species is wanting; but, on the contrary, some careful observers tell us, in their books on Hunting or Natural History, that numerous species of birds will soon become extinct.
3rd. Birds are not, as the author of the memoir calls them, "unintelligent assassins." Far from this, they kill by preference the most injurious insects. The time at which they carry on a really murderous war is when they are feeding their young. But what do they feed them with? With very few insectivorous insects; the latter, armed and mailed—carabi and stag-beetles—covered with metallic scales, equipped with hooks and pincers, of an indestructible vitality, would be a horrible food for the young of the warbler, who, before such a provision, would assuredly take to flight. This is not the kind of aliment the sagacious mother seeks for her offspring; but soft and, as it were, milky insects, fat and succulent larvæ, fine little tender caterpillars,—all herbivorous, fructivorous, and leguminivorous animals; exactly those which do the greatest mischief in our fields and gardens.
Accordingly, the great labour of the bird against the insect precisely coincides with the labour of the husbandman.
For the rest, we are far from saying, as the author referred to makes us say, that the bird is the sole purifier of creation. One must be blind, and indeed senseless, not to see that he shares this mission with the insect. The action, too, of the latter is undoubtedly more efficacious in the pursuit of a world of living atoms, which the insect, whose eyes are microscopes, detects and pounces upon in numerous obscure corners, inaccessible to the bird. The bird, on the other hand, is the essential purifier of everything demanding long-sightedness and the power of flight,—as, for example, the frightful clouds of invisible animalcules which float and swim in the air, and therefore pass into our lungs.
As a rule, the equilibrium of species is desirable. All are more or less useful. We willingly join with the author of the paper referred to in the wish that those insects which prey upon the smaller species might be specially distinguished and spared. The peasant destroys them indiscriminately, without knowing that by killing, for instance, the dragon-fly (or libellula)—the brilliant murderess which slays a thousand insects daily—he is helping the latter: becomes the auxiliary of the insects, the preserver and propagator of the enemies which devour his substance. The terrible cicindela does not fly so high, but with its crossed daggers, or rather the two scimitars which serve it for jaws, accomplishes a swift and almost incredible havoc among the smaller insects. Take care, then, and respect it. Do not listen to the child who is dazzled by the beauty of its wings, nor, to please him, impale on the needle-point your admirable insect-hunter, the efficacious auxiliary of the agriculturist!
The carabi,—immense warrior-tribes armed to the very teeth, and displaying an ardent activity beneath their heavy coats of mail,—are the true guardians of your fields; and day and night, without holiday or repose, protect your crops. They themselves never touch the smallest blade or seed. Their sole occupation is to capture thieves, and they ask for no other reward than the thieves' bodies.