Like all long-lived creatures, the Rook is temperate in eating, and he is capable of going a long time without food--a faculty which stands him in good stead during hard winters. In a long frost or a prolonged drought he is a most determined robber, and when he is on what he knows to be forbidden ground, he posts a sentinel to give warning of the approaching farmer or watcher. He is known to take the eggs of such favourite birds as the thrush and the blackbird, whose nests are open, and therefore soon discovered and plundered. But this is no doubt where his proper food is scarce; and if man had not been so eager in the destruction of some of our birds of prey, who are the natural enemies of him and his, Rooks would be less plentiful in some districts. Still, I for one have no desire to see their numbers decrease, so certain am I of their value; and I believe this bird will become even more valuable as time goes on. The Rook is somewhat smaller than the Hooded Crow; the beak more slender, rather straighter; the base of it in mature age bare, and covered with a kind of white scurf. The entire bird is black with a steely-blue and purple gloss. The feet black and thick, the claws strong, the sole rough; it walks better than the Hooded Crow. The beak of the young bird is not bare, the nostrils being covered with bristly feathers. The bareness first appears when the bird begins to dig in the ground for its food. [Illustration: The open nest tempts the Rook.] THE HOODED-CROW. (_Corvus cornix._) The Hooded Crow walks well, with head erect, moving its tail right and left as it goes. Its flight is easy, using comparatively little movement of the wings. This Crow usually makes its nest in the tops of high trees, preferably in one standing alone in a field; but sometimes on rocks. It does not build in colonies but usually settles alone, though occasionally two or three pairs will build on the edge of a wood or in a small plantation. The nest consists of twigs, roots, and grass; the hollow of the nest being safely lined; in the spring it contains four to six eggs of a light green colour speckled with grey and brown marks. In mild seasons this bird has been known to pair, as early as the end of February, but the usual time is March. Then the construction and arrangements of the nest begins. The female bird, only, sits on the eggs; the male guards the nest and provides the food. When near the nest, he is a courageous, even daring bird, able to keep off such enemies as the Hawk or the Eagle. His cry is “_kár, kár_.”