“ANIMALS arrived, liked the look of the place, took up their quarters, settled down, spread, and flourished.

They didn’t bother themselves about the past – they never do; they're too busy.”

So mused Ratty the water vole in Wind in the Willows. “Weasels and stoats and foxes and so on … pass the time of day when we meet, and all that … but you can’t really trust them, and that’s a fact.”

Ratty knew something even his creator Kenneth Grahame didn’t at the time. His nemesis reared its head on British riverbanks in 1929.

Resembling something between a small cat and a ferret, the American mink is bigger and stouter than other stoats and weasels. Streamlined to swim with the minimum of resistance, the stealthy interloper’s long body helps him to get into the burrows of his prey.

Released from fur farms and breeding in our waterways by 1956, the predator from across The Pond was soon devouring fish and water voles at an astounding rate. He also took ducks, cygnets, moorhen, rabbits, and a variety of small mammals.

Absent from the Monnow from about 1980, “Ratty” was on the very brink of extinction.

Joining forces with the Monnow Rivers Association, the Game and Wildlife Conservation Trust came up with plans to redress the balance. To improve the habitat in the Monnow catchment they built fencing to keep livestock out of the river and increased coppicing to allow more light on to the riverbank. With better river conditions for trout, lush and vegetated banks also breathed fresh life into the flora and fauna.

Stage two of the initiative was to stop the mink in his tracks – literally.

Noting that he is instinctively curious and investigates unusual holes, tunnels or objects, the GWCT set about developing a “mink raft”.

Research found that it’s possible to place clay lined tracking pads in tunnels on rafts and detect which kinds of mammals are using them. Once the inquisitive mink has investigated a floating raft and left scat or footprints, a trap can be placed under the wooden housing. He will generally be trapped within a few days, and rafts can then be moved to other minkmonitoring locations.

The new approach had two advantages over existing techniques.

Firstly, it saves time because weekly checks are all that are needed until the traps are set when daily checking becomes necessary. Secondly, with trapping taking place only on rafts where mink are known to be visitors, it reduces the chance of catching other species, such as polecats, which are not being targeted.

By the spring of 2011, with momentum also gathering in the control of another vigorous invader, Himalayan balsam, water voles had colonised new areas of the lower Dore and the main River Monnow.

And it’s not just Ratty who has been making a comeback: the little grebe or dabchick, an excellent swimmer and diver, is back skilfully using vegetation as a hiding place. Like all grebes, he nests at the water's edge because he doesn’t walk very well.

Kingfisher and moorhen, declining in the 1970s and 80s, are also gaining a new lease of life.

Taking a celebratory dip into the Golden Valley there’s a chance we may sneak a glimpse of the iconic water vole. The Dore is opening for Ratty. The mink is no longer taking over at Toad Hall. 4¼ mile moderate walk in The Golden Valley.

Water meadow, pasture and brookside. “Ratty’s” domain along the Dore at A and B.

Map: OL 13.

Public Transport: Bus 39.

THE ROUTE 1. Car parking space opposite St Bartholomew’s Church, Vowchurch , SO 363 365. Facing church, TR over bridge crossing the Dore along road into Turnastone.

Pass Turnastone Court, Church and The Shop. Bend Right 60m and cross a stile on your left.

2. “Long Meadow”. Keep to the left in long pasture to cross a stile 20m in from far left corner. Bear R in “New Meadow”, slowly moving away to the right from the fence and Slough Brook.

Head for far right corner and leave meadow via stile on to road opposite drive up to Cothill. TL along road for ¼ mile. Just after passing a footbridge (left) and just before Slough Bridge and St Margarets sign, TR through wooden gate up to left of plantation. Cross stile in top left corner, TR under trees past marker post and go up through ferns into pasture.

Bear L quite steeply up over tarmac drive (to Dolward Farm) and join drive leading into Cothill.

3. Cothill Farm. Cross cattle grid straight ahead between barn conversion and farmhouse to leave farmyard via gate other side of buildings.

Follow right edge/hedge through gate ahead. Go ahead 60m through k-gate, TL to resume same line across stile ahead. Bear L down through gate (L of trees) and go half R in next pasture. Go along little channel through (open?) gate, TL along L edge fence (left of barns ahead). (Ignore right turn). Go through gate over farm track just 20m and go through the gate on your R.

4. Shegear Farm. TL and go diagonally down sloping pasture towards bottom right edge of wood in front of you.

Go through (open?) gate at tree edge and now take the right option down the pasture on the edge of the other (Green’s) Wood. (Peterchurch church spire, ahead left).

Cross stile and keep descending along the left edge. Cross stile and go half R in front of trees and then head for left corner of meadow to the brook.

5. Trenant Brook. When you reach f/bridge and ford, do not cross but TR on yourself to follow the bank of the brook downstream through three gates past Poston Court Farm on other bank.

Go through fourth gate, and 25m beyond f/bridge on L, TL across stile and immediately through gate ahead. Go along avenue with fence R and Trenant Brook still L. Reach f/bridge into Poston Mill. Do not cross, TR through gate into meadow. Follow Dore, with a chance of seeing water vole, towards Turnastone church. Go through gate by river elbow, orchard and gate to road. TL back to Vowchurch Bridge for another chance to see “Ratty”.

(Nearby also at Nag’s Head bridge and Peterchurch church bridge).

 Thanks to Robert Denny of the MRA for his help.