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Survey water voles

Why water voles?

Water voles are disappearing. They started to lose their homes in the 1940s and 50s with the intensification of agriculture, but the most devastating blow came during the 1980s and 90s. Illegally released American mink spread furiously across the countryside, preying on the vulnerable native mammals, which they continue to do today. In just ten years, water vole numbers crashed by almost 90%.

People’s Trust for Endangered Species launched the first National Water Vole Monitoring Programme (NWVMP) across Britain in 2015 to establish how many water voles remain and where they live. This vital knowledge is fundamental to the UK water vole conservation effort.

Why we need your help

With your help, we will:

  • Monitor water vole presence/absence, as well as relative abundance, at sites across England, Scotland and Wales annually so we can detect any changes in their populations and distribution.
  • Collect records of mink and otter at these sites, as well as information about whether any mink control is carried out.

We recommend you read our guide at the bottom of the page about what each step of the process involves. If you’d like to take part, please register here.

How to take part

We’re asking you to survey a 500m stretch of waterway once a year, between 15th April and 15th June. You will record all water vole field signs that you do or do not see, along with otter and American mink. Full guidance will be given and our survey training materials are available to read here.

To get started, please register here. Then, select a site to survey or create a new site.

After you register, you can visit your site and plan your survey route. Once you have carried out your survey, you can submit your records online. Even if you don’t spot any water vole signs, please still submit your records.

More information

If you already record water voles at a local site but it is not listed among our pre-selected sites, you can add it to the survey when you register.

Please note: for the NWVMP we ask you to monitor your site every year so we can more easily compare. If you would like to report a one-off sighting of a water vole, please do this via your Local Environmental Records Centre. They will be able to add it to their records and feed the information into the National Water Vole Database and Mapping Project, which is run by The Wildlife Trusts.

+ Selecting a site to survey (pre-selected sites)

We have carefully selected nearly 900 sites across England, Scotland and Wales that were surveyed during the two past Vincent Wildlife Trust surveys. It is really important to go back to these original sites to get robust data on how the population of water voles in the UK is faring.

After registering as a surveyor you will be able to select one or more of these sites by entering your postcode/town on our Google map. After you have selected a site it will no longer be available for another volunteer to choose.

Next, you will need to visit your chosen site in advance of the survey (15th April to 15th June) and plan your 500m survey route or ‘transect’. See details below.

+ Registering a new site

If you are already surveying a site (or number of sites) for water voles, or you know of a suitable site near where you live that you would like to monitor, you can add them to the NWVMP once you have registered as a surveyor. Each site should ideally have a continuous 500m transect that can be surveyed annually to tie in with the other sites that will be surveyed. However, if this is not possible then a shorter transect (any denomination of 100m) can be surveyed. We would also encourage you to take on one of the other original sites too so that we can try and get as many of these sites monitored each year.

Please note that to register a site, you will need to know:

  • The grid reference of your site
  • The county your site is in
  • The name of your site
  • Habitat of the site and waterway type
  • Number of transects at the site and their start and end grid references
  • Whether mink are controlled at the site
  • Whether water voles have been reintroduced at the site

Once you have successfully registered your site, you will be all set to carry out your survey between 15th April and 15th June. See details at the bottom of this page.

+ Visiting your site and planning your survey route

Before carrying out your survey you will need to visit your chosen site so you can:

Complete the site information form

We will ask you to complete a form with the following information:
• The habitat your site is in
• The water way type you will be surveying along
• Whether you know if there has been a water vole reintroduction at the site
• Total number of transects at the site (for most sites this will be one)
• Whether mink control happens at the site

Plan where your survey route will start and end

You will need to survey one bank of a 500m stretch of waterway (transect) at your site, recording any field signs within each 100m section. We recommend you also test walk your planned route to check it is suitable, measure out the distance and record the start and end grid references (instructions will be given).

Get permission from the landowner and give them the landowner questionnaire

You MUST get permission from the landowner if you need to enter private land to conduct your survey. We will provide a landowner permission letter for you to print out and take with you which identifies you to landowners and explains what you are doing.

Please also give the landowner a copy of our landowner questionnaire and ask them to complete it and return to us at our freepost address.

+ Carrying out your survey

To carry out your survey you will need to:

Time your survey correctly

You must survey your site between 15th April and 15th June. Surveys can be conducted on any day during this period and at any time of the day. Your survey should take about 45 mins – 1 hour to complete.

Surveys should not be conducted during times of flooding or heavy rain. Please wait at least two days after the water levels have subsided to allow field signs to accumulate and be visible.

Ensure you take the correct equipment with you

Please ensure you take all the equipment listed in the guidelines (provided later) with you when you go to do your survey e.g. printed maps, guides and forms, a mobile phone. No specialist equipment is needed.

Walk your transect recording any water vole, otter and mink field signs

In each 100m section of your transect you will need to record all feeding signs (each pile of chopped vegetation counts as one), latrines (trampled and untrampled piles of dropppings), burrows/nests and sightings on your survey form. An ID guide will be given.

The grid reference/GPS position of the first and last latrine in each 100m section must be recorded as a minimum. Again the guidelines give simple instructions how to do this.

If you see signs of otter (spraint/sightings) or mink (scats/sightings) and are certain of your identification, you will also record these in the relevant section of the recording form provided.

+ Completing your survey

Ensure your recording forms are complete

You will need to make sure all relevant sections of the paper recording forms are completed when you finish walking your transect.

Submit your records online

Back at home/work you MUST enter your records online to make all your efforts pay off. Please submit all your records by the 31st October each year. Even if you didn’t find any signs of animals during your surveys we would still like you to submit your negative records.

For any further information or to ask a question, please reach out to our Water Vole Officer, Emily Sabin at


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We'd love to tell you about our conservation work through our regular newsletter Wildlife World, and also how you can save endangered species through volunteering, taking action or donating. You must be 18 or over. The information that you provide will be held by People’s Trust for Endangered Species. For information on how PTES processes personal data, please see our privacy policy.

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