BIRDS ON THAMES RESERVOIRS
Now that every large town and many small ones are adding new reservoirs, often of great size, to hold their water supply, these artificial lakes play an important and increasing part in the wild life, not only of the country, but of cities, and even of London itself. Immense reservoirs have been made near Staines, and others are being added close to the London river. These quiet sheets of water, carefully protected from intrusion for fear of any pollution of the water, form artificial sanctuaries which not only fill with fish, which the water companies encourage, to eat the weeds and insects bred in the weeds, but attract wild-fowl of very many kinds in ever-increasing numbers. In Hertfordshire the artificial lakes near Tring made to supply the Grand Junction Canal are carefully preserved, and have a large and resident population of wild-fowl (we believe a bittern bred there recently, and the great crested grebe is common), and some of the new London reservoirs are rapidly attracting a stock of wild-fowl. Thus civilisation is in some measure restoring the balance of wild life, and offers to the most persecuted of our birds a quiet and secure retreat. I was able at the close of February, 1902, to witness a striking example of the results of wild-bird protection in increasing some species of wild-fowl which for half a century had steadily dwindled and disappeared, and were practically unknown anywhere in the neighbourhood of London. The scene was on the very large new reservoirs which lie between the grounds of the Ranelagh Club and the Thames, on what was some seven years ago a tract of market gardens and meadows. The construction of these lakes was so ably planned and carried out that in two years from the turning of the first sod four wide pools, covering in all one hundred acres of ground, were ready to be filled, and at the end of 1898 the ground was metamorphosed into the largest area of water in the London district, with the exception of the Serpentine.
It is so rare for changes of this magnitude to take place in any other way than by covering what was open ground with bricks and mortar, that the advent of a kind of reservoir flora and fauna so close to the greatest city of the world was looked for with some curiosity. All the waste ground not covered by the water or filtering-beds produced quantities of brilliant flowers, as waste ground enclosed and left to itself generally does. The banks and broad walks between the lakes were sown with good grass, which was regularly made into hay. The reservoirs themselves soon filled with fish, which came down the mains from Hampton, where the water is taken in from the river. What these reservoir fish found to live upon at first is not clear. No weeds are allowed to grow either in the water or on the banks, which are concreted. But the bottom becomes covered with the suspended matter deposited from the unfiltered water, and probably a considerable number of the minute entomostraca beloved of all fish breed in this. The Barnes reservoirs do contain a growth of weed, which is carefully removed every year. Whatever their sustenance may be, these reservoirs are very full of fish, both the old ones at Barnes and the new lakes near Ranelagh. The supply of fish, and the open and strictly private extent of water, then attracted a number of wild duck or water birds of some kind, which the writer was invited to see and identify, as it did not seem probable that they could be the ordinary wild duck, which are vegetable feeders, and would need an artificial supply of grain, which is provided on the Serpentine, but is not given to any of these reservoir ducks. They have appeared entirely uninvited. The scene over the lakes was as sub-arctic and lacustrine as on any Finland pool, for the frost-fog hung over river and reservoirs, only just disclosing the long, flat lines of embankment, water, and ice; the barges floating down with the tide were powdered with frost and snow-flakes, and the only colour was the long, red smear across the ice of the western reservoir, beyond which the winter sun was setting into a bank of snow clouds. It was four o'clock, and nothing apparently was moving, either on the ice or the water, not even a gull. In the centre of the north-eastern reservoir was what was apparently an acre of heaped-up snow. On approaching nearer this acre of snow changed into a solid mass of gulls, all preparing to go to sleep. If there was one there were seven hundred, all packed together for warmth on the ice. It is on or about these reservoirs that the London gulls now sleep. Sometimes they are there in thousands; but the sealing of so much of the water with ice had sent a great proportion of them down the river to the more open water of the Essex marshes. Beyond the gulls, which rose and circled high above in the fog with infinite clamour, were a number of black objects, which soon resolved themselves into the forms of duck and other fowl. Rather more than seventy were counted, swimming on the water near the bank or sitting on the ice. These were the self-invited wild duck, so tame that with very little trouble they were approached near enough for their colour and form to be distinctly visible. The result of a look through the glasses was something of a surprise. They were not mallard, teal, or widgeon; but three-quarters of the number were tufted ducks, a diving-duck species, which haunts both estuaries and fresh water, but preferably the latter. It is a very handsome little black-and-white duck, seen in great numbers on certain large lakes in Nottinghamshire, and has greatly increased of late years in the county of Norfolk. But so far it has not appeared in any numbers either on the Surrey ponds or in Middlesex, and its assembling on this London reservoir is a remarkable proof of the tendency of wild-fowl to increase in this country.
The cock birds were in brilliant winter plumage, with large crests, white breasts, and white "clocks" on their wings. Some were sleeping, some diving, and others swimming quietly. When approached, the whole flock rose at once, and flew with arrow-like speed round the lakes and twice or thrice back over the heads of their visitors, of whom they were not at all shy, being used to the sight of the man who keeps the reservoirs' banks in order. They swept now overhead, now just above the ice, like a flock of sea-magpies or ice-duck playing before some North Atlantic gale. As several birds had not risen, we ventured still nearer, and saw that most of these were coots, some ten or eleven, which did not fly, but ran out on to the ice. Two large birds remaining, which had dived, then rose to the surface, and to our surprise and pleasure proved to be great crested grebes. These birds, which a few years ago were so scarce even in Norfolk that Mr. Stevenson despaired of the survival of the species as a native bird, have bred for three seasons in Richmond Park. But their presence so close to London shows that we need not despair of seeing wild-crested grebes appear on the Serpentine. These birds are so wedded to the water that they rarely fly. But this pair rose and flew, not away from, but towards us, passing within fifteen yards. With their long necks stretched out, feet level with the tail, and plumage apparently painted in broad, longitudinal stripes, they presented a very singular appearance.
The East of London owns a crowded wild-fowl sanctuary at Wanstead Park, which quite a different class of ducks frequent. It is now the property of the public, and very carefully administered by trustees. The lake there is very narrow and winding, which causes it to freeze easily. On the other hand, it is full of long, densely wooded islands, some almost enclosing pools of water. These islands shelter the birds, and when the lake is covered with ice the islands are crowded with wild duck and widgeon. Wanstead is a curious example of the faith of wild-fowl in a sanctuary, for the lake is so narrow that you could toss a stone among the fowl from the bank. Suburban houses are close by on all sides but the meadows by the little river Roding. Yet the fowl come to the lake as confidently as they do to great sanctuaries like Holkham. As there is a large heronry and rookery on the trees on the islands, the variety of life there is very great. The writer saw in weather like that in the second week of February, 1902, about a hundred and fifty wild duck, thirty or forty widgeon, a few teal, a pochard, and a great number of water-hens. Mallard, teal, dabchicks, and moorhens breed there regularly, and in hard weather a number of rarer birds drop in. Snipe are often seen by one of the shallower ponds, and occasionally such divers as goosanders appear and give an exhibition of fish-catching. These, like the tufted ducks and grebes, are entirely self-supporting. The wild duck are pensioners, being fed artificially, though they are wild birds, or descended from birds which were wild, just as are the London wood-pigeons.