It must not, therefore, be supposed that every one flying alone is a crow. Crows are scarce in comparison with rooks. In severe weather a rook will sometimes venture into the courtyard of the farmstead. Two rooks marked with white resided at the rookery here for several years. One had sufficient white to be distinguished at a distance; the other seemed to have but one or two feathers, which were, however, visible enough when near the bird. As they have not been seen lately, they have probably been shot by some one who thought it clever to destroy anything out of the ordinary. Most large rookeries can either show a rook with white feathers, or have well authenticated records of their former existence; but though not rare, people naturally like to preserve them when they do occur, and it is extremely annoying to have them wantonly killed. CHAPTER FIFTEEN. ROOKS RETURNING TO ROOST--VAST FLOCKS--ROOK PARLIAMENT--THE TWO ROOK ARMIES AND THEIR ROUTES--ROOK LAWS, TRADITIONS, AND ANCIENT HISTORY--"THROWS" OF TIMBER--THIEVING JACKDAWS. As evening approaches, and the rooks begin to wing their way homewards, sometimes a great number of them will alight upon the steep ascent close under the entrenchment on the downs which has been described, and from whence the wood and beech trees where they sleep can be seen. They do not seem so much in search of food, of which probably there is not a great deal to be found in the short, dried-up herbage and hard soil, as to rest here, half-way home from the arable fields. Sometimes they wheel and circle in fantastic flight over the very brow of the down, just above the rampart; occasionally, in the raw cold days of winter, they perch moping in disconsolate mood upon the bare branches of the clumps of trees on the ridge. After the nesting time is over and they have got back to their old habits--which during that period are quite reversed--it is a sight to see from hence the long black stream in the air steadily flowing onwards to the wood below. They stretch from here to the roosting-trees, fully a mile and a half--literally as the crow flies; and backwards in the opposite direction the line reaches as far as the eye can see. It is safe to estimate that the aerial army's line of march extends over quite five miles in one unbroken corps. The breadth they occupy in the atmosphere varies--now twenty yards, now fifty, now a hundred, on an average say fifty yards; but rooks do not fly very close together like starlings, and the mass, it may be observed, fly on the same plane. Instead of three or four layers one above the other, the greater number pass by at the same height from the ground, side by side on a level, as soldiers would march upon a road: not meaning, of course, an absolute, but a relative level. This formation is more apparent from an elevation--as it were, up among them--than from below; and looking along their line towards the distant wood it is like glancing under a black canopy.