Wolves are again howling through the woodlands of western Germany for the first time in 150 years, after spreading back into Western Germany now that most of their natural enemies have disappeared, conservationists say.

Wolf sightings have been common in Poland and eastern Germany for several years, but never in the heavily urbanised and industrial heartland of the Ruhr Valley and the Rhineland - until now.

Front-page tabloid headlines shocked city dwellers recently with reports that at least one wolf is on the prowl in North-Rhine Westphalia, Germany's most populous state and a region which borders on France.

Wildlife experts used DNA fingerprinting to confirm that a farmer's sheep had been killed by a wolf. It is the first report of a wolf attacking livestock in this part of Europe since the mid-19th century, when industrialization forced wolves to retreat to eastern Europe.

Ironically, the post-industrial era in Germany's ageing rust belt coincides with environmental awareness and conscious efforts to restore the balance of nature. In addition, the fall of the Iron Curtain 20 years ago has made east-west travel easier not only for humans, but also for wolves.

As wolves are encroaching on urbanised areas, they have even been spotted on the outskirts of large cities like Berlin.

Red foxes are also on the increase, again facilitating the return of wolves, which feed on foxes and their pups.

Experts say the disappearance of lynxes and brown bears in the 20th century has helped to reverse the fall in the fox population.

Without those natural enemies, foxes have been able to establish themselves as the dominant carnivore in many areas of Central Europe.

And with the foxes roaming again across Western Europe, wolves are following literally in their footprints. The widespread eradication of rabies has also been a boon to wild canine families, since rabies has always been the primary biological enemy of these creatures.

“It is only a matter of time before wolves spread all across Germany in their move ever-westward,” says Professor Josef Reichholf of the University of Munich.

Wolves and foxes are only the start of a resurgence in wildlife unseen since the Middle Ages, the biologist predicts.

“Weasels and otters and racoons are already well re-establishing themselves,” he says. “And the European moose elk is poised to move westward. Indeed, elk are already relatively common in the Czech republic.”

Mr. Reichholf says it is not the food that humans eat which interests foxes so much as the animal companions of humans - rats, mice, pigeons - and also the plentiful and often overflowing garbage that humans generate.

This does not mean that wolves - naturally shy creatures - will be moving into cities.

“Wolves are certainly welcome here as they enrich the local wildlife assortment,” says Volker Boehning, head of the state hunting association in the state of Brandenburg, adding that any excess population would be tackled by hunters.

But canine carnivores, such as foxes and wolves, also help other species, such as song birds.

“They decimate not only mice but also other small mammals and snakes and other egg thieves,” says Torsten Reinwald of the German Hunting Association. “We actually get appeals from residents to kill more foxes because they are eliminating too many predators in some nature wildlife preserves.”

Germany will be a turning point for the wolf population, according to Professor Reichholf. “This is the region where we shall see whether the wolf spreads further westward and, if so, in what numbers,” Mr, Reichholf says.

“The main problem will be the cliche of the ‘big bad wolf’ in the minds of many people. Wolves can, of course, be dangerous to humans in certain situations, generally when they are backed into a corner. But they are generally no threat to humans,” he says.

Working in favour of the wolf's spread across Europe is a change in the mindset of modern-day humans.

“Europeans generally are very mindful of the dire effects that humans have had on the environment over the centuries,” he says.

“As more predators move in, the balance of nature returns to normal and we see a reduction in rats and mice and rabbits,” he says.

“Those small creatures form the diet of predators such as the German Sea Eagle, which was the emblem of Germany for centuries but which was driven to the verge of extinction by unthinking hunters.”

Now, he says, the German Sea Eagle is once again being spotted over the coastal forests of Germany - forests which, if you listen carefully at night, are again ringing of the howl of wolves.