Save the environment – eat an oyster

'Kill it! Kill the damn thing!" Never before have I heard such words coming from a vegetarian.

But, despite appearances, being in this wilderness has not caused my fellow oyster-hunter to abandon her ethics. In fact, our mission is to restore equilibrium in this precarious ecosystem, and the oyster is public enemy No 1.

We are standing on a wind-battered mussel bank, just off the western coast of Jutland. A thin strip of the Wadden Sea coastline, along with a clutch of small islands, forms Denmark's newest National Park. This "eat as much as you can" oyster safari is one of the responsible tourism projects hoping to benefit from the area's new status.

With our backs to the weather, we watch with morbid fascination as Sten, our guide, thrusts a blade inside the shell of his arch nemesis. He explains that tourists like us are the only line of defence against the 500 tons of oysters breeding here. In the 1960s, an attempt to breed them for mass consumption failed commercially, but those that broke out have multiplied at a rate that threatens the native mussel population, and the birds that feed on them.

A trickle of sea water seeps from the shell and, with the artful swish of a knife, our guide has become our waiter. Sten offers me the oyster but, though I would love to do my bit, I am not accustomed to eating my food quite this fresh. Luckily there are many other takers on hand, one of whom has lugged champagne and lemons over the mudflats to enhance the al fresco dining experience.

As we wade landwards, laden with oysters, I stop to survey the emptiness. Having grown up on the edge of the Lake District, to me "National Park" has always meant high drama. My horizons were filled with black mountains that made the Romantics quiver, and John Constable skies that looked set to fall in on you at any moment. Instead, this level landscape resembles half a cup of milky tea spilt across a blank canvas.

Yet the strange clarity of the light has a hypnotic quality. And there is something else: after just a short time here, you begin to feel the incessant flux that underlies the apparent stillness. I peer into a rockpool that teems with darting life forms. I disturb a hedgerow and some caramel-winged thing flaps out. In the March and October migration seasons, the reed beds along this coast swarm with starlings and, at dusk, you can take a "black sun safari" and watch them bed down.

It was on such a tour that I found myself in a blustery field, feeling rather underdressed among a group of well-togged birdwatchers. Those with binoculars would occasionally lower them, squint, and point at some invisible object of interest. Just as despondency was creeping in, a black, twisting form appeared out of the pale distance.

And then, suddenly, they were there in their thousands. Throwing spiral shapes, tubes and arches, the starlings' motion was as fluid as a gymnast's ribbon. As they dipped, they revealed a glimpse of their ringmaster, a sleek, bullet-shaped hawk. For several minutes he commanded them in this synchronised dance and, just as he gave up and the starlings dropped into the reeds, a new, larger group came coiling into view.

Twice a year, these wetlands are a rest stop on the migratory route, but once these spectacles are over, there are many other nature-centred activities to enjoy. The Wadden Sea Centre in Ribe runs seal and goose-spotting trips, as well as tractor rides to Mando, a tiny island that can be accessed over land only at low tide.

In summer, vast sandy beaches attract the more laid-back customer. Romo, the largest of the National Park's islands, has some of the widest beaches in Europe. You can drive along them, fly kites, ride sand buggies or take to the sea and windsurf.

The best base for exploring the park is Ribe, the oldest city in Denmark and one-time trading hub of Scandinavia. It has endured fires, plagues and floods to become the serene, well-preserved town it is today. Its modest river once jostled with shallow-hulled Viking boats bringing glass from Italy and exotic goods from the Middle East. Beyond it, the vast, expansive horizons beckoned the Vikings toward new lands of promise.

Now this coast beckons the hordes back: one of the principal aims of conferring National Park status was to market the area to tourists. "This is no longer just 'the Wadden Sea'," says Sten, as we dry off back at base. "We have branding now, an identity." But he must dash; he's off to greet a busload of elderly ladies from eastern Germany. He's a little daunted. "I haven't spoken German since high school, and for a start, I can't remember all their different words for 'seal'."

Off he goes, for another tour, and I head back to Ribe as the tide is coming in, slowly engulfing sparse sprigs of samphire. The sun is sinking over the reed beds now, and above them a hawk is once again lurking, ready to start this evening's show.

Compact Facts

How to get there

DFDS Seaways (0871 882 0886; dfds.co.uk) offers return ferry travel from Harwich to Esbjerg for £249 each way for a family of four in a sea-view cabin, including carriage of a car. Ribe Byferie (ribe-byferie.dk) offers three nights at its holiday centre from DKK1,890 (£216). Europcar (00 45 89 33 11 33; europcar.com) rents cars from DKK1,893 per week.

Further information

The Wadden Sea Centre (00 45 75 44 61 61; vadehavscentret.dk) offers oyster trips from DKK175 per person.

Visit Denmark (020-7201 3982; visitdenmark.com). Black Sun Safari (sortsafari.dk).