17 DECEMBER 1910, Page 10

ITU! WAYS OF ROOKS.

AN interesting account was given to a recent meeting of the British Ornithologists' Union by one of the members, Mr. Griffith, of a remarkable flight of rooks. Mr. Griffith told the meeting that on getting out of the train at Orpington Station in Kent, about twenty minutes past four on the afternoon of November 14th, he saw an extraordinary number of rooks passing in a steady, continuous stream for sixteen and a half minutes, apparently making for Farnborough, which lies about a mile away. He described them as "winging their way in a great column of from fifteen to twenty abreast, and moving at about ten miles per hour." On the lowest estimate he reckoned that about thirteen thousand passed over him, but how many bad already passed before he stepped out at the railway station he could not say. Mr. Griffith seems to have been undecided as to whether these rooks were native birds returning from the day's foraging to their roosting-trees, or whether they were foreign birds coming to take up their residence here. Both sup- positions are possible, but it is quite likely that what Mr. Griffith witnessed was the arrival of part of the large army of rooks which reaches us every autumn, generally between the third week in October and the middle of November, from Scandinavia and the North of Europe. Great flights of rooks of this kind have been recorded before from various parts of these islands; for instance, in the autumn of 1893, when large numbers were seen by home-bound Atlantic ships as far as three hundred miles from the West coast of Ireland. The rooks settled on the spars and rigging of the vessels, almost too weak to move, and they were thus brought within sight of the Irish shore, when they flew off. Flights of thousands of

rooks were also reported that year from the Scilly Isles and from Lewis. In other years-1884, 1887, and 1889, for instance—many hundreds of rooks were observed by lighthouse- keepers on the south-west of Ireland, flying in from the west. Where did they come from ? The nearest land to the west is America.

Other members of the crow family migrate in the same way, particularly hooded crows, which every year reach the Eastern counties from the Continent in flocks about the same time In the autumn. It will be noticed that Mr. Griffith saw Lis flight of rooks in an Eastern county, and that they were flying south-west. Of similar autumn migrations to other countries, one of the most remarkable is chronicled by Howard Saunders, who mentions that late in November, 3880, great flocks of rooks made their appearance in Iceland. The probability is that these were migrating Scandinavian rooks blown out of their way by a gale of wind ; but to cross from the nearest point of Norway they must have flown over six hundred miles of sea.

These great winter gatherings of rooks, whether they are liative birds or migrants, are of course a common feature of the bird life of this country. The actual numbers of any one concourse are extremely difficult to calculate, but the writer made an attempt to estimate the number which he saw in a wonderful gathering in Kingston Vale early in February this year. The rooks were scattered over the fields between the Beverley Brook and the woods of Coombe Warren, and there was another large detachment in the fields between the brook and Putney Vale. In one part near Robin Hood Farm there was a space of about five acres, as near as could be judged, which was simply black with rooks. If there was one bird to the square yard, there must have been nearly twenty- five thousand rooks in that space alone, and there were other places where they were almost as thick. The curious point was that though the writer left Kingston Vale to catch a train only because it was getting too dark to see the way back across Wimbledon Common, there seemed to be no tendency on the part of the rooks to fly away to roost for the night. Some of them at least, perched in the hedgerow trees, appeared perfectly satisfied with their quarters, and it is possible that they may have stayed there. We do not know as much as we might about the roosting habits of rooks in winter. The data are insufficient upon which to build satisfactory theories. What we know is that it is only in the nesting season that rooks roost actually in the rookery trees, and that in high summer they leave the rookeries and join in large flocks, which retire for the night to roosting-places in deep woods. They may be seen passing overhead in the early morning, flying out to their feeding-grounds, and coming back in the afternoon, always at the same time and flying in the same direction ; but it by no means follows that a person watching the rooks fly out and home every day will be able to discover where they feed by day or where they roost at night. The writer has watched rooks fly over his garden for years past, but has never been able to trace them to the trees where they roost. They fly almost (hie east and west, but an attempt to trace them home leads merely to losing them in the sunset. Water. ton, one of the most persistent of all observers of the habits of rooks, gives us a delightful account of the morning and evening flight of the birds of the neighbourhood over his park. The rooks which he watched belonged in winter to Nostell Priory, about two miles distant, where, he writes, "from time immemorial the rooks have retired to pass the night. I suspect," he adds, "by the observations which I have been able to make on the morning and evening transit of these birds, that there is not another roosting place for at least thirty miles to the westward of Nostell Priory." But Water- ton does not mention migrant rooks, and one of the points which it would be interesting to be able to settle would be the relations of the autumn immigrants to the native birds. Do the newcomers join existing flocks, or do they keep their companies apart?

We might be able to come a little nearer to solving some of the problems of the natural history of these fine birds if we knew the numbers of the rooks which remain with us for breeding. It is a matter which would really present no diffi- culty if the right authorities would take it up. If the County Councils, or, better still, the Board of Agriculture 'working through the County and Parish Councils, would take a census of rookeries in the spring, the numbers of rooks would be ascertained at once; all we should want to know would be the number of nests with broods, which woald give us the breeding stock ; and then, if another census were taken the next spring, we could tell whether rooks were on the increase, and if so, to what extent,—a matter of real importance for the farmer, now that the habit of eating grain and other crops appears to be more prevalent than before. We know, of course, that the number of rooks in this country has always been very large. Waterton writes of the rooks passing over his park as "congregated thousands upon thousands," and there is an illuminating case which was decided in the Law Courts in 1824, in which the plaintiff alleged that the defendant had broken up his rookery; he had fired guns near the close where the birds nested, and "with the noise of the discharging of the said guns and the smell of the said gunpowder" he had driven away the rooks "inso- much that divers, to wit 1000, rooks, which before that time had been used and accustomed to resort, &c., flew away and abandoned the said close and trees and the nests built therein, and wholly forsook the same, and divers, to wit 1000, other rooks which were then about to resort to and settle in and upon the said close and trees, were thereby prevented from so doing." A rookery of two thousand parent birds is a fair-sized menage for any estate. What are the corvine traditions and instincts that the young birds of these great rookeries inherit ? They do not all of them return to build in their parent rookery the following season, but when do they decide that a new rookery must be established ? And bow many rookeries are there in the country now, as compared with the days when "divers, to wit 1000, rooks" could be frightened away from their trees by the smell of gunpowder ? We do not know, and it would be valuable knowledge if we did know ; but our Department of Agriculture has not yet decided that the knowledge is worth acquiring, even at the slightest possible expense.

Waterton has a very interesting passage, in dealing with the flight of rooks, in which he describes what he calls the " shooting " of the rooks. "He who pays attention to the flight of birds," he writes, "has no doubt observed this down- ward movement. When rooks have risen to an immense height in the air, so that, in appearance, they are scarcely larger than the lark, they suddenly descend to the ground or to the tops of trees exactly under them. To effect this, they come headlong down on pinion a little raised, but not expanded in a zigzag direction (presenting alternately their back and breast to you), through the resisting air, which causes a noise similar to that of a rushing wind. This is a magnificent and beautiful sight to the eye of an ornithologist." Does the local name for this evolution, allied as regards the sound produced by the bird's wings to the "drumming" of the snipe, still survive in Yorkshire ? Waterton says that the local farmers think that it portends wind, though be him- self does not. But, oddly enough, he does not mention a curious and beautiful evolution which he must often have seen his homing rooks go through in high winds such as those of the past week, which is, to fly home in eddying circles, now high and now low, perhaps twenty or thirty birds at a time. It is a fascinating thing to watch, especially when the companies of birds reel across the sky one after another under grey clouds tearing from the south and south-west. The rooks seem to separate into twos and threes which keep close together, and go tossing in a sort of spiral rotation, always, whenever the writer has watched them, from right to left—the opposite way of stirring a cup of tea—and apparently thoroughly enjoying the whirling and dipping, the beat up into the wind and the sudden relaxation of effort as the breeze catches and spins them round again.