Townies don't need the countryside

Those fanatical bird-watchers, the "twitchers", who stop at nothing for a sighting of a rare visitor to Britain, made a beeline last week not for some wild and windswept acre of countryside but for an exclusive enclave in Barnes where a house was sold recently for £2.8 million. Thirty of them packed the hide at the London Wetland Centre to train their telescopes on a tall, aloof-looking wading bird standing among the reeds, a beady eye on the look-out for fish, eels and passing water voles. For the first time in perhaps a century a bittern had turned up in Barnes and it was joined a few hours later by two more.

The boom of the bittern in the breeding season was once an eerily familiar sound in the English countryside, especially in the reed beds of East Anglia when cottages were thatched and the wetlands extended for miles. From the 1950s they suffered a dramatic decline and now there are thought to be only just over 20 in the whole country. In winter a few lope across the Channel on broad, bowed wings and look for a secluded haven which will keep them fed until spring.

But why should they light upon 100- odd acres in Barnes, which until five years ago was a Thames Water reservoir with not a reed in sight?

However thrilling it is for wildlife enthusiasts in London to have a bittern in their midst, it should really come as no great surprise, for it is a mere prejudice that wild birds, animals and plants prefer the countryside. What they are after is food and shelter, and postal districts mean nothing to them.

From the ground-floor kitchen window at the back of my home in urban Highbury, N5, I saw yesterday morning: a mistle thrush, a flock of long-tailed tits, a small warbler called a whitethroat, a cormorant, Canada geese and a blackbird in the space of about 10 minutes. I keep a pair of binoculars handy and especially enjoy the aerial dog fights between the kestrels (a pair nested this year in a nearby church ) and carrion crows. Sometimes there is a heron involved as well. Grey squirrels squabble with magpies, and the crows dive-bomb foxes, which appear in broad daylight on the roofs of garages at the back of my house.

Why would I see a fisheating bird like a cormorant in Islington? Because we are on the flight path between the River Thames, where the cormorants go to fish, and Walthamstow Reservoirs to the northeast where they roost. Skeins of Canada Geese are on the same flight path between the central London parks and Walthamstow. I discovered this while filming a wildlife series called City Safari for ITV a few years ago. We were able to shoot a beautiful sequence of great crested grebe with their young on the Serpentine - this bird was hunted to near extinction in Britain at the turn of the century because its wing feathers were prized as "Grebe furs" - and to film house martins collecting mud for their nests in the stucco rosettes of the French Embassy from a rainwater pool at the end of the lake.

We made a special study for that series on the wildlife in the 39 acres of Buckingham Palace gardens, which is a "green island" in the city. For decades two London naturalists regularly recorded more than 20 species of breeding bird, including the mallard ducks which nest on the windowsills of the Palace, then lead their brood to the lake in St James's Park with a police escort. In the first surveys, 260 species of wild plant were identified, including the rare adder's tongue fern.

Because it is cut off by a high wall which prevents most mammals from getting in, Buckingham Palace Garden had no foxes or rabbits, though both could be found only a short hop away in Hyde Park. In the winter of 1996, a fox did get into the garden - the Palace refused to reveal how - and slaughtered the celebrated pink flamingos which had become frozen by their feet in the lake.

The dramas of the natural world are acted out in the city just as they are in the countryside and, as the arrival of the bitterns in Barnes has shown once again, "habitat" does not have to be ancient or rustic to attract wildlife. The great crested grebe is a case in point. Much of its recovery can be attributed to the building, between the wars, of the arterial roads, and the motorways which left behind gravel pits, which then became fresh water lakes where the grebes have bred in large numbers. The London Wetland Centre at Barnes already has two pairs as well as 10 pairs of little grebe.

In just five years a remarkable nature reserve has been created in London which already attracts such a quantity of wild ducks in winter that their numbers are considered of national significance. The wetlands of Barnes that have now attracted the bittern, were created because Thames Water built a new ring main and did not need an old reservoir. Even before the derelict filter beds were taken over by the Wildfowl and Wetland Trust (WWT) they had become attractive enough to wildlife to be classified as a Site of Special Scientific Interest. Twentyfive acres were sold to Berkeley Homes, which put some of the £11 million it raised from the sale of exclusive houses into creating the nature reserve. Thames Water and the WWT did the rest.

Nearly all of the wildlife turns up of its own accord , including fish, which arrive in a feeder stream that runs from Hampton. Water voles have been introduced and some of them will no doubt make a snack for the bitterns, herons and foxes of the centre. Happily mink, which escaped from fur farms in the Fifties and have colonised much of Britain, have not yet found their way to Barnes.

It is unlikely that the bitterns will stay at the London Wetland Centre once spring comes because birds require much larger areas if they are to breed. But they have been known to boom in February, and it is just possible that the lucky residents of Barnes will be among the very few people in Britain to hear that eerie sound this year.

?For further information about London's wildlife, call London Wildlife Trust on 020 7261 0447.