The bloody results are plain to see. In the past two months around 100 sheep and cattle have been killed near Buitrago, in the northern foothills of the Guadarrama mountains, says Juan Carlos Blanco, a wolf specialist and adviser to the Spanish Environment Ministry.
"Guadarrama can support two, even three, packs. We think there are now six packs within 100km of Madrid.
"When they arrive in a new area the shepherds do not know what to do. Then they find ways to protect their flocks with dogs or fences.
"It's a natural event and the wolf will not go away now. Maybe hunters will exterminate one pack, but others will take its place. Wolves are very flexible and resilient."
Spain is now a wolf stronghold. While the population had diminished to just a few packs in isolated regions in the 1960s, there are now thought to be more than 250 breeding groups and more than 2000 individuals.
"As wolf numbers grow so does the number of attacks on animals. From 2005 there were about 1500 attacks a year. Then in 2008 it jumped to over 2000," says Luis Suarez, World Wide Fund for Nature (WWF) biodiversity officer in Madrid. "In the past seven years 13,000 sheep, 200 goats and several hundred cows have been attacked across Spain."
In the 19th century the European wolf was almost driven to extinction as hunters made a living from the bounties paid by villagers.
But conservationists are surprised at how fast wolves have returned during recent years, populating areas where they were last seen more than 100 years ago.
Wolf populations in Europe quadrupled between 1970 and 2005 and there may now be 25,000 animals, says the International Union for Conservation of Nature. They have been seen within a few kilometres of major cities including Berlin, Rome and Athens. Last month one was found near the Dutch hamlet of Luttelgeest, just 50km from Holland's densely populated North Sea coast.
They are also reportedly expanding their range in France, Germany, Poland, Scandinavia and Italy, with sightings in Belgium and Denmark.
In the past 10 years, says Blanco, wolves have arrived in the Pyrenees from Italy and the Alps.
"They have crossed 450km and a lot of roads to get there. So far they are not breeding there, but it's only a matter of time," he says.
In Germany, where they were hunted out of existence in the 19th century, there are now thought to be around 160 wolves in 17 packs in the state of Brandenburg.
Wolves traditionally flourish in times of political and economic crisis. Their return to Europe in the past 20 years is thought to be linked to widespread rural depopulation and the collapse of the Soviet Union.
The demise of the USSR saw a near 50 per cent increase in the number of wolves in the 1990s, as animals that had been kept under control by state-sponsored culling were left to roam unchecked and many packs crossed into sparsely populated areas of Poland, Germany and Scandinavia.
Some conservationists say the economic recession in Spain, Portugal, Greece and elsewhere has also helped them spread into new areas.
"People have migrated from rural areas, allowing the wolf to reoccupy abandoned land. The recession has left less money for farmers to protect their animals," says Suarez.
"Land is being abandoned. The woods regrow, so there are more deer, less hunting pressure, and more food for wolves," says Peter Taylor, British ecologist and editor of Rewilding journal, who lives in the Czech Republic.
"Wolves are returning to many of their old haunts in Europe and also wandering into long-forgotten territory.
"There are breeding pairs now in Germany, Slovakia, Poland, Romania, Croatia, alpine Italy, the Apennines and alpine France."
Blanco, who expects to see numbers continue to grow in the next decade, says: "Wolves have always been hated by country people, but they do not threaten people. We must help farmers tolerate them."
But the image of the wolf as a danger to be exterminated is strong in countries to which it has recently returned. Its re-emergence has pitted conservationists against farmers furious that wolves are killing their livestock.
Wolves are a protected species but many are now being hunted illegally and poisoned.
Spain's Environment Secretary Federico Ramos says: "It's not the devil, it's just an animal. We must learn to live together."
- Observer
