THE endangered water vole – immortalised as Ratty in Wind In The Willows – has returned to Suffolk’s riverbanks, according to a survey which reveals dozens of “hotspots” for the animal.

The tiny mammal saw its numbers plummet by 90% in 2005 because of predation by invasive mink and loss of its natural environment.

However, it was given full legal protection two years ago, making it a crime to intentionally kill or injure a water vole or disturb their habitats, in a bid to protect them.

Now data gathered from 36,000 individual surveys across the UK, released today by the Environment Agency, has identified more than 30 “hotspot” sites for the mammal – and Suffolk is no exception.

Water vole occupancy of the River Deben catchment alone has increased by 40% from 2003 to 2006.

Until 2008, water vole populations had disappeared from almost the whole of the River Stour and the situation was thought so severe that a release of captive-bred animals was being planned.

However, in 2008 the first water vole was spotted and the recovery of the population was confirmed by a survey that found them around Bures and at other locations along the river.

The results are thanks to a combination of the best river water quality for more than 20 years, habitat improvement work and control of mink, the water voles’ main predator.

The Environment Agency has brought about some of these changes directly but a partnership project, called Water for Wildlife (WfW), has also had enormous benefits.

Major work areas include giving advice on mink control, organising water vole and otter surveys and advising landowners.

Chris Strachan, from the Environment Agency’s fisheries, recreation and biodiversity team, said: “The improvements in the water vole’s fortunes are due to the hard work and dedication of lots of people, many of them working voluntarily.

“It is very heartening to be involved in such a project involving agencies, project officers and landowners all working towards a common goal.”

But the data also shows how badly the animal is faring in some parts of the country, prompting Alastair Driver, the Environment Agency’s national conservation manager and chairman of the UK water vole steering group, to warn there is still “a long way to go” before populations return to healthy levels.