Graham Holyoak – Restoring Ratty Project Officer, Northumberland Wildlife Trust
July 2020
I am writing this having just completed our 7th release of water voles, with over 1700 animals released in total so far. The eighth release is just a couple of weeks away so we are preparing for this now. It seems a long time ago when I sat down to start the first phase of the project back in 2013!
The idea for reintroductions actually started long before this with Forestry Commission (now Forestry England) surveying the rivers in Kielder Forest back in 2008, and the then Forest Management Director Graham Gill suggesting that a reintroduction would be a good fit in an operational Forest. On the back of this idea , a lottery bid was submitted in 2009 which unfortunately failed, and it wasn’t until 2013 that a partnership of Tyne Rivers Trust, Forestry Commission and Northumberland Wildlife Trust received funding from the National Lottery Heritage Fund for a two year Water Vole Heritage Project. This aim of this project was to show that there was a suitable mink free habitat for water voles and that the local community was supportive.
On the successful completion of this project with no confirmed mink found we applied for further funding from the National Lottery Heritage Fund to begin bringing water voles back… and so the Restoring Ratty project was born!
Kielder Forest is the largest man-made forest in England and lies in Northumberland on the Scottish border. It produces 20% of all the timber in England. Over the last 30 years, changes in forest management practices have changed the dark stream sides with conifers down to the edges, to an area of excellent riparian habitat for water voles as planting of new trees is now done further back from the banks.. This process is ongoing so the amount of habitat for voles carries on increasing. Forestry England’s Wildlife rangers had been controlling mink since the 1990s meaning that there was very few left in the forest.
Restoring Ratty is unusual in water vole reintroductions, as the donor animals for our captive breeding programme come from wild populations rather than the usual method of removing water voles from building development sites. Voles were captured from sites in the North Pennines, North Yorkshire Moors and the Trossachs in order to create a wide genetic pool to breed from – with genetics similar to the water voles that would originally have been in Kielder. In order to not harm the donor population we only captured voles in later summer that were smaller than 160g and would be unlikely to survive the winter. The voles were transported down to Derek Gow Consultancy (DGC) in Devon for breeding.
The first 317 voles were ready in June of 2017 for our big first release! Along with a team from DGC it was the chance for our amazing volunteers to see voles back in Kielder after close to 4 years of monitoring for mink! This was followed by a further release in August 2017 and then every June and August to the present day!
We employ a soft release method where voles are put into a straw filled pen on the edge of a stream at the release site. They are then fed with apple and carrot for several days to allow them to acclimatise to their new surroundings, and in the case of paired voles – hopefully breed. A wooden plate with two holes is then placed over one end of the pen and this allows the voles to come and go as they please, but prevents most predators getting in. Some voles are eager to go and head off into the wilds as soon as the plate is put on whilst others are more tentative. By the time we remove the pens a few days later a handful of times have we had to evict a water vole!
The criteria we use to choose our water vole reintroduction sites have changed over time as well. Prior to the project, a feasibility study was conducted looking at habitat suitability from the water vole handbook. Well it is safe to say that some of our water voles haven’t read the handbook! We initially put them in streams with lovely earth banks and widths of between 1-3 metres with a mix of grass and herb vegetation. Where they seem to thrive in Kielder are very small ditches often around 30cm width. As per best practice, we have also often conducted surveys along burns looking at the banks and the 2m zone on each side and found little. Feeling despondent on the walk back, further away from the burn we have stumbled across some feeding signs or a latrine tucked away in some rushes or a burrow under a tussock or the scampering of a water vole through the vegetation over 10m away from the streams. These small streams and ditches are now our release sites of choice – you have to listen to the voles!
We have continued the mink monitoring from the first phase throughout the project mainly using mink rafts. We have around 60 rafts that are checked on fortnightly basis by volunteers, land owners and project staff. Mink rafts are essentially a floating platform containing a tunnel with a clay and sand tracking pad inside with floral foam to keep the clay moist. We have been trying to make the rafts more environmentally friendly and reduce plastic loss to the environment. We use recycled plastic rafts and wrap the polystyrene that provides the buoyancy to ensure that this does not wash away. We have also been trialling substitutes to the floral foam using coir (coconut husk) and that has worked well in some situations. We have also increased our use of camera traps and have tried baiting them further away from water vole locations. It seems that mice are very fond of tinned sardines as surprisingly are red squirrels! We have found that mink numbers are low although we have had a couple of incursions that we have had to deal with so vigilance and continued mink monitoring is paramount.
We only have a year left of Restoring Ratty – but this cannot be the end. We have a commitment to carry on the mink monitoring to ensure that this reintroduced population is safe. That is not the extent of our ambitions though. Our ultimate aim is to link up the new population with the nearest donor population some 40 miles away in the North Pennines. We are looking at a phase 3 of the project to continue this progress with further releases to boost the natural recolonisation of the water voles as well working to improve habitat and remove mink. We have recently had some good news on this front with a partnership of Durham Wildlife Trust, Tees Valley Wildlife Trust and Northumberland Wildlife Trust receiving funding from National Lottery Heritage Fund for a three year mink control project in the Tyne, Wear and Tees catchments.
A final note on the 2020 releases – they have been very strange as we haven’t been able to have our volunteers with us due to COVID19 restrictions. The volunteers have been integral to every part of the project from helping with events, mink monitoring, water vole monitoring and the releases. It is not an exaggeration to say that we could not have done this project without them and so although the water voles may be the stars our volunteers are not far behind!
L to R; The pringles tube, perfect for vole handling. Ratty Ale, innovative fundraising! One of the first water voles released.
Follow the work of the Restoring Ratty project on their Facebook page.
Scottish Invasive Species Initiative 