This great stream of rooks passing over the hills meets another great stream as it approaches the wood, crossing up from the meadows. From the rampart there may be seen, perhaps a mile and a half away, a dim black line crossing at right angles—converging on the wood, which itself stands on the edge of the table-land from which the steeper downs arise. This second army is every whit as numerous, as lengthy, and as regular in its route as the first.
Every morning, from the beech trees where they have slept, safe at that elevation from all the dangers of the night, there set out these two vast expeditionary corps. Regularly the one flies steadily eastward over the downs; as regularly the other flies steadily northwards over the vale and meadows. Doubtless in different country districts their habits in this respect vary; but here it is always east and always north. If any leave the wood for the south or the west, as probably they do, they go in small bodies and are quickly lost sight of. The two main divisions sail towards the sunrise and towards the north star.
They preserve their ranks for at least two miles from the wood; and then gradually first one and then another company falls out, and wheeling round, descends upon some favourite field, till by degrees, spreading out like a fan, the army melts away. In the evening the various companies, which may by that time have worked far to the right or to the left, gradually move into line. By-and-by the vanguard comes sweeping up, and each regiment rises from the meadow or the hill, and takes its accustomed place in the return journey.
So that although if you casually observe a flock of rooks in the daytime they seem to wander hither and thither just as fancy leads, or as they are driven by passers-by, in reality they have all their special haunts; they adhere to certain rules, and even act in concert, thousands upon thousands of them at once, as if in obedience to the word of command, and as if aware of the precise moment at which to move. They have their laws, from which there is no deviation: they are handed down unaltered from generation to generation. Tradition, indeed, seems to be their main guide, as it is with savage human tribes. They have their particular feeding grounds; and so you may notice that, comparing ten or a dozen fields, one or two will almost always be found to be frequented by rooks while the rest are vacant.
Here, for instance, is a meadow close to a farmstead—what is usually called the home-field, from its proximity to a house—here day after day rooks alight and spend hours in it, as much at their ease as the nag or the lambs brought up by hand. Another field, at a distance, which to the human eye appears so much more suitable, being retired, quiet, and apparently quite as full of food, is deserted; they scarcely come near it. The home-field itself is not the attraction, because other home-fields are not so favoured.
The tenacity with which rooks cling to localities is often illustrated near great cities where buildings have gradually closed in around their favourite haunts. Yet on the small waste spots covered with cinders and dustheaps, barren and unlovely, the rooks still alight; and you may see them, when driven up from such places, perching on the telegraph wires over the very steam of the locomotives as they puff into the station.
I think that neither considerations of food, water, shelter, or convenience, are always the determining factors in the choice made by birds of the spots they frequent; for I have seen many cases in which all of these were evidently quite put on one side. Birds to ordinary observation seem so unfettered, to live so entirely without rhyme or reason, that it is difficult to convey the idea that the precise contrary is really the case.
Returning to these two great streams of rooks, which pour every evening in converging currents from the north and east upon the wood; why do they do this? Why not go forth to the west, or to the south, where there are hills and meadows and streams in equal number? Why not scatter abroad, and return according to individual caprice? Why, to go still further, do rooks manoeuvre in such immense numbers, and crows fly only in pairs? The simple truth is that birds, like men, have a history. They are unconscious of it, but its accomplished facts affect them still and shape the course of their existence. Without doubt, if we could trace that history back there are good and sufficient reasons why rooks prefer to fly in this particular locality, to the east and to the north. Something may perhaps be learnt by examining the routes along which they fly.
The second division—that which goes northwards, after flying little more than a mile in a straight line—passes over Wick Farm, and disperses gradually in the meadows surrounding and extending far below it. The rooks whose nests are placed in the elms of the Warren belong to this division, and, as their trees are the nearest to the great central roosting-place, they are the first to quit the line of march in the morning, descending to feed in the fields around their property. On the other hand, in the evening, as the army streams homewards, they are the last to rise and join the returning host.
So that there are often rooks in and about the Warren later in the evening after those whose habitations are farther away have gone by, for, having so short a distance to fly, they put off the movement till the last moment. Before watches became so common a possession, the labouring people used, they say, to note the passage overhead of the rooks in the morning in winter as one of their signs of time, so regular was their appearance; and if the fog hid them, the noise from a thousand black wings and throats could not be missed.