What we offer

Greenlight Environmental Consultancy offers various services with respect to water vole surveys, including:

  • Preliminary Ecological Appraisal (“PEA”) –This is an initial site assessment to identify habitats present on site that may support protected species. This includes a site visit and a desktop assessment. A PEA is typically required as a first step to address the ecological aspects of a planning application. The PEA would recommend if further water vole surveys are necessary, and appropriate mitigation and enhancements for the proposed development.
  • Waterway and pond bank survey – This type of survey aims to assess the use of a waterway or a pond by water voles through a search for water vole signs which include faeces, latrines, feeding stations, burrows, footprints, runs or pathways.
  • European Protected Species Mitigation Licences – If works are expected to have an impact on water voles or on their breeding and resting sites, a mitigation licence will need to be granted by Natural England in order to proceed with the works.
  • Translocation works – This includes trapping and moving water voles to a safe and suitable receptor site with a sufficient carrying capacity for the affected population. This can only be done under a mitigation licence granted by Natural England and should be used as a last resort.
  • Overseeing works – This can involve supervising the strimming of banks when mitigation includes water vole exclusion, or ensuring that adequate buffer zones to protect water vole burrows are marked out and respected.


The water vole is the largest species of vole in Britain (adults weight between 140-350g). Although its morphology is not particularly adapted to water (no webbed feet or flat tail), the water vole can swim and dive in a doggy-paddle style, with its head and back visible.

Water voles are herbivorous, and have been found to feed on up to 227 species of plant (Strachan, and Jefferies, 1993). If they are disturbed while feeding on the bank, they will purposely slash dive into the water with a characteristic ‘plop’ sound to warn other voles.

Water voles do not hibernate over winter but they spend more time in their burrows and are therefore less visible above ground.

The species is thought to have been lost in up to 90% of the sites where it occurred in the last century. The principle threats to water voles include habitat loss, degradation, and fragmentation primarily from unsympathetic riverside management, and predation by the introduced American mink Neovison vison.


The water vole is a priority conservation species and is protected under the following UK and European Union (“EU”) law:

Under this legislation water voles are protected from:

  • Capturing, killing, injuring and disturbing;
  • Damaging or destroying breeding/resting places;
  • Obstructing access to resting places; and
  • Possessing, advertising for sale, selling or transporting for sale, live or dead (part or derivative).

In simple terms: all development proposals which have the potential to impact on local biodiversity, and Local Planning Authorities (“LPA”) require sufficient information to make informed decisions that wildlife can be protected from injury or disturbance during the development. They often require a Preliminary Ecological Appraisal (“PEA”), and further water vole surveys if the species is likely to be present. 


In the UK, water voles are mostly found on grassy banks along slow moving and relatively deep (over 1m depth) water courses, lakes and ponds. They prefer sites with wide swathes of riparian vegetation growing both from the banks and from the water which they will use both as food and shelter. Water voles dig burrows in steep and easily penetrable banks, which often include underwater entrances and which can be several meters deep into the bank.



Water vole surveys are best conducted between April and September, however, signs of presence can be found from March to November. Surveys should not be undertaken when waterways and ponds are flooded, as any field signs would be washed away. For this reason, water vole surveys should be conducted at least two days after the water levels subside.

Water Vole surveys (timings)

Mitigation and enhancements

When activities are likely to have a negative effect on water voles, a mitigation strategy tailored to avoid the specific issues on the site should be put in place. Water vole mitigation will most often include maintaining a buffer zone to avoid works to the areas where water voles are, and ensuring habitat maintenance and connectivity. If this is not possible, the vegetation cover of the bank may be removed to encourage water voles to voluntarily move to a connected habitat. In a situation where no other alternative was available, the capture and translocation of water voles to a suitable receptor site may be considered. Compensation and enhancement methods may involve providing further habitat for water voles, improving water quality, and enhancing bank vegetation structure.



Dean, M., Strachan, R., Gow, D. and Andrews, R. (2016) The Water Vole Mitigation Handbook (The Mammal Society Mitigation Guidance Series). Eds Fiona Mathews and Paul Chanin. The Mammal Society, London.

Natural England. (2008) Water voles – the law in practice: Guidance for planners and developers. Natural England, Peterborough.

Strachan, R., Moorhouse, T. and Gelling, M.  (2011) Water vole Conservation Handbook (third edition). WildCRu: Oxford.

Strachan, R., and Jefferies, D.J. (1993) The Water Vole Arvicola terrestris in Britain 1989-1990: its distribution and changing status. The Vincent Wildlife, London.