Little bustards and flat-bottomed barques in the jungles of France

Eerie but tranquil, the Poitevin Marshes are an ideal spot for Francis Jezierski and family to enjoy a water-borne foray

Things started to go adrift as we turned left off the river Sèvre Niortaise. Christopher, who's eight, had been paddling well. His big brother Joseph, on the other side of the boat, was paddling even better. There was a disparity. Sitting awkwardly in the back, my left leg in plaster, I had, despite my lack of canalmanship, kept us on a reasonably direct course while we remained within the doubting gaze of the mademoiselle from whom we had hired the boat. "Stop paddling, Joe! Go, Christopher!" I would order as we proceeded swerve by gentle swerve down the watery highway.

But the effort of balancing the mis-matched powers of two boys proved too much as we entered the still, enclosed narrower channel leading into the ancient labyrinth of the canals and conches of the Poitevin Marshes, a part of Vendée adjoining La Rochelle which makes up in mystery what it lacks in more blatant allure. Our flat-bottomed, rudderless barque was not as other boats. The front would nose its way into the tall, sturdy rushes lining the high banks while the rear continued serenely on its way, until we faced the way we had come and continued backwards.

It would have been laughable, had there been anyone to laugh at us, but though we were still in Damvix (height above sea level: four metres), this was an eerily empty world.

Here gardens straggled down to the weed-covered water. Landing stages and barques lay in disintegration, testimony to the decline of these waterways as the area's means of travel and communication. As we left the last of the shuttered, seemingly uninhabited old properties, the silence was broken only by the splashing of our paddles and an early summer breeze rustling through the alders and poplars along the water's edge. Sometimes the trees merged into darkening avenues that spanned our route, shards of sunlight piercing the canopy and playing on the green, still water ahead of us. Smaller canals opened up on either side, many rendered impassable by tangled roots, prompting dark thoughts of what secrets those long-unvisited routes might hold. Gradually we tamed our wilful craft, and plunged deep into this extraordinary waterscape by the Atlantic, whose inhabitants for centuries struggled to coexist with and overcome the ever-present flooding from the network of rivers whose way to the sea was blocked by the very land they inhabited.

King Henri IV wrote to his mistress Corisande that he had fallen for the charms of a land "which forms a huge natural Venice". The area is still known as Green Venice, though unlike its namesake it is not yet overrun by tourist hordes. These canals, started by monks in mediaeval times and extended during the Napoleonic period, do not have towpaths and even though we were there during a British half-term holiday, there were few others on the water. When we stopped paddling, birdsong and the hum of dragonflies were the only sounds. Sometimes we also heard the rasping of unseen beasts grazing beyond the high banks, to the consternation of Christopher, a townie to his fingertips.

We let the boat drift in the breeze as we ate a picnic lunch by one of the innumerable junctions, slowly turning circles until, in this alien, undifferentiated world, we no longer knew which way we had come or were going. There are 4,000 km (2,500 miles) of canals and other waterways here – 4,000 chances, as one website puts it, to get lost, helpfully suggesting a map should be acquired in advance. Without one, it adds, you can always ask directions from a passing boat, "eventually, perhaps..." Certainly, though, there was little chance of getting lost where we were: the routes are signposted, because the marshes, though protected, are promoted as a tourist attraction. Most villages have boats, including electric ones, for hire, some with guides. Restaurant boats cruise the larger waterways. Like the restaurants hereabouts, they proudly feature eels (ugh!), abundant in the marshes. The "wet marshes", where the navigable canals are, make up the eastern part of the region, formed by the silting up of the bay.

From the 11th century onwards, monks built canals to drain the land, a process later continued by Dutch engineers. Their legacy is a fertile landscape of "dry marshes" which at once resemble the American prairies and the Netherlands. The prairies because they are flat, almost treeless and with big, big skies; the Netherlands because of the complex system of polders, canals and raised roads. You are reminded you are in France by the lonely villages which rise from this expanse, protected by their remoteness from development and Brits.

The marshes are a favourite area for birdwatchers, being particularly noted for sandpipers, little bustard and aquatic warbler. Thousands of migrating birds stop on the estuary of the Sèvre Niortaise. The canals have a rodent of endearing appearance called a nutria and otters, now threatened by the prospect of agribusiness and mass tourism. The area is being turned into an attraction for cyclists, with 45km of track already in use and 120km due for completion in 2005 under the rather menacingly termed "Plan Vélo".

Our leisurely, sometimes ludicrous, often entrancing voyage took us through little more than a few kilometres of the countryside around Damvix, and the whole of the afternoon. For my boys, that was enough canal, thanks. With a kayak, however, far longer, faster and more adventurous journeys are feasible.

The Poitevin Marshes are not Brittanny, and from the coast here, La France is not belle. Fortunately, though, we were staying at a five-star campsite, in a well-appointed and spacious mobile home. There was a fine swimming pool, pool tables and satellite television, with a remarkably large screen. Boy heaven. At this time of year much of the site was still empty, so the queues which normally provide a perfect excuse for not playing football, tennis and mini-golf were not there.

Fortunately, though, I had my broken foot instead, and was able to sit and paint outside the caravan unmolested. Camp life for my two teenage daughters was not so diverting, though they found little time left between barbecues, beach walks and the opportunities to shop provided at La Tranche, our local resort.

We were too busy this time to visit the region's vast and extraordinary Futuroscope theme park, but we did tour the splendid aquarium at La Rochelle. Which in turn worked up the family's appetite for a marvellous seafood dinner on Ile de Ré ... And why was I sporting a broken foot? Don't even ask.

The Facts

Getting There

Francis Jezierski and family travelled as guests of Canvas Holidays (01383-629 000; www.canvasholidays.co.uk), staying at the five-star Camping du Jard site in La Tranche-sur-Mer. A seven-night holiday for two adults and up to four children costs from £626 in June. The price includes a return crossing with Brittany Ferries from Poole to Cherbourg for a car and up to six passengers and accommodation in a Century mobile home.

Being there

To hire a barque at Damvix costs €14 (£10) an hour. There are many other places where boats can be hired.