The population of water voles at Rutland Water is now thriving, thanks to a successful reintroduction project. Read more here.
Water voles are members of the rodent family, and, as the name suggests, like to live near water. They occur at the fringes of ponds, lakes and other bodies of still water such as canals, but are just as at home on the banks of rivers and streams. They live and breed in burrows that they dig into the soft mud of the banks, and feed mainly on vegetation such as reeds.
Historically, water voles were widespread throughout Britain, but their population suffered a dramatic decline during the 20th century – one of the most serious declines of all British mammals. This population decline was due mainly to the presence of mink, but also habitat fragmentation and water pollution. Mink are a non-native species that were brought to the UK in the 1920s for use in fur farms, and either escaped or were released, and had begun breeding in the wild by the 1950s. Unfortunately, mink are very efficient at predating water voles, as they can easily follow voles into their escape burrows. A single female mink can wipe out a small population of water voles within 48 hours.
The decline of the water vole was noticeable everywhere in the UK, and the following graph shows the reduction in numbers seen around Rutland.
It was soon realised that something needed to be done to replenish the population of water voles at Rutland Water. Consequently, a license was applied for to undertake a reintroduction project in suitable habitat on the nature reserve.
Prior to the licence being granted, extensive surveys for field signs were carried out throughout the Rutland catchment area by our staff and volunteers in order to establish the current status of water voles in Rutland. Unfortunately no recent signs of water vole activity were identified in Rutland, but plenty of relict holes from populations past were found throughout the River Gwash and corresponding water bodies. Past records gathered from the public confirm the physical evidence.
The licence was granted, and in May 2011 a re-introduction programme for water voles took place in conjunction with a programme of mink control.
As mink are the main threat to water voles, their presence on the reserve needed to be monitored. Mink are monitored on the reserve using special mink detection rafts, which consist of a tunnel-like structure with a clay base. The clay then retains the tracks of any animal that walks on it. Happily, so far we have found no sign of mink. Footprints that have been identified include water vole, rat, otter, moorhen and domestic cat!
In May 2011, 80 water voles were initially released onto the nature reserve. Then, in early August, 160 voles were brought to the reserve and were acclimatised for a few days in release pens placed throughout the reserve, in what is known as a soft release method. The voles were kept in pens for three days to give them time to adjust to their new surroundings. On the third day, wooden baffles were placed at the front of the pen allowing the voles to come and go as they pleased for a further two days before the pens were removed.
The population of water voles on the reserve has been monitored closely ever since the re-introduction, by volunteers Linda and Anthony Biddle. These surveys are carried out by the simple but effective method of counting the number of droppings on specially made “rafts”. Water voles like to keep their burrows clean by using flat areas of mud or grass as latrines. They will also often use areas such as this as feeding stations. With this in mind, several small rafts were made and installed in all locations likely to contain water voles. The voles then use these rafts as latrines, and surveyors visit the locations of these rafts and count the number of water vole droppings that appear on them. Based on the results of these surveys, it is safe to say that the reintroduction project was successful, and water voles have become well established on the nature reserve.
These water vole surveys are carried out every quarter, and results recorded and analysed. The population will continue to be monitored over the coming years. The other ongoing task is to continue to monitor the presence of mink, which is done using the mink rafts mentioned above. Click here for Linda Biddle’s report on the reintroduction.
Seeing water voles
Water voles are not a species that can be spotted easily, as they are rather elusive and live mainly under the protective cover of tall waterside vegetation. If you are lucky you may see one swimming away from you, but more likely you will just hear the “plop” of them entering the water when they hear you coming. Water voles have often been spotted in the channels in front of Waderscrape hide on the Lyndon reserve, and here you stand more of a chance of seeing them sitting on the banks, as there is the advantage of being able to sit in the hide and make no noise, making it more likely they will show themselves.
Here are some photographs of water voles that volunteer Sue James took during an osprey monitoring shift in Waderscrape hide. Thank you for letting us share these, Sue!