Here is a fine study by Jefferies of the behaviour of rooks en masse, from ‘Wild Life in a Southern County’ (1879). His close observations of their habits eventually lead him to conclude that they, like humans, have their own history etched into the landscape.
“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.
Small outlying parties straggle from the line – now on one side, now on the other; sometimes a few descend to alight on trees in the meadows, where doubtless their nests were situated in the spring. For it is a habit of theirs months after the nesting is over, and also before it begins, to pay a flying visit to the trees in the evening, calling en route to see that all is well and to assert possession.
The rustling sound of these thousands upon thousands of wings beating the air with slow steady stroke can hardly be compared to anything else in its weird oppressiveness, so to say: it is a little like falling water, but may be best likened, perhaps, to a vast invisible broom sweeping the sky. Every now and then a rook passes with ragged wing—several feathers gone, so that you can see daylight through it; sometimes the feathers are missing from the centre, leaving a great gap, so that it looks as if the bird had a large wing on this side and on the other two narrow ones. There is a rough resemblance between these and the torn sails of some of the old windmills which have become dark in colour from long exposure to the weather, and have been rent by the storms of years. Rooks can fly with gaps of astonishing size in their wings, and do not seem much incommoded by the loss – caused, doubtless, by a charge of shot in the rook shooting, or by the small sharp splinters of flint with which the birdkeepers sometimes load their guns, not being allowed to use shot.
Near their nesting-trees their black feathers may be picked up by dozens in the grass; they beat them out occasionally against the small boughs, and sometimes in fighting. If seen from behind, the wings of the rook, as he spreads them and glides, slowly descending, preparatory to alighting, slightly turn up at the edges like the rim of a hat, but much less curved. From a distance as he flies he appears to preserve a level course, neither rising nor falling; but if observed nearer it will be seen that with every stroke of the wings the body is lifted some inches, and sinks as much immediately after-wards.
As the black multitude floats past overhead with deliberate, easy flight, their trumpeters and buglemen, the jackdaws – two or three to every company—utter their curious chuckle; for the jackdaw is a bird which could not keep silence to save his life, but must talk after his fashion, while his grave, solemn companions move slowly onwards, rarely deigning to “caw” him a reply. But away yonder at the wood, above the great beech trees, where so vast a congregation is gathered together, there is a mighty uproar and commotion: a seething and bubbling of the crowds, now settling on the branches, now rising in sable clouds, each calling to the other with all his might, the whole population delivering its opinions at once.
It is an assemblage of a hundred republics. We know how free states indulge in speech with their parliaments and congresses and senates, their public meetings, and so forth: here are a hundred such nations, all with perfect liberty of tongue, holding forth unsparingly, and in a language which consists of two or three syllables indefinitely repeated. The din is wonderful – each republic as its forces arrive adding to the noise, and for a long time unable to settle upon their trees, but feeling compelled to wheel around and discourse. In spring each tribe has its special district, its own canton and city, in its own trees away in the meadows. Later on they all meet here in the evening. It is a full hour or more before the orations have all been delivered, and even then small bands rush up into the air still dissatisfied.
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 tableland 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 eastwards 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 dust-heaps, 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, nor 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. Some¬thing 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.
By Richard Jeffries, Visionary Author and Naturalist (1848-1887)