Otter Surveys
Otters & the Law
Otters in the UK are protected under the Wildlife and Countryside Act 1981 (as amended) and the Conservation of Habitats and Species Regulations 2017. It is an offence to intentionally kill, injure, disturb or take otters, or to damage, destroy or obstruct access to otter holts (resting places) or breeding sites, without a licence.
Early ecological assessment helps identify whether otters or their habitat may be affected by development, reducing the risk of legal or planning issues. Survey results support planning applications and, where necessary, mitigation and licence applications.
When is an Otter Survey Required?
Otter surveys are typically required where proposed works may affect watercourses, wetlands, ponds, ditches, riparian habitats, culverts, bridges or adjacent land that could be used by otters for commuting, feeding, or resting. Survey evidence may be requested as part of a planning application even where no otter records exist, because the presence of suitable habitat can indicate potential use by otters.
Completing surveys early helps determine whether targeted survey effort is needed and aligns with planning timescales.
Typical habitat
While rivers are most often thought of as the typical river habitat, they may also be found in lakes, streams, coastal areas or even ditches connecting habitat. As well, the riparian habitat along the banks is very important and can include woodland, grassland, scrub, bogs, reed beds or any other vegetated habitat along the water. Otters will often walk along the river banks rather than swim in the water while traveling so any development along the river (particularly roads and bridges) can inhibit their range. Otter holts (dens) or couches area are also usually found within the riparian habitat rather than in the water itself. Both the water bodies and the surrounding riparian areas are important for otter survival.
Phase II otter surveys
If the Phase I survey has identified habitat that may be used by otters, further surveying may be required if there is any potential for this habitat to be impacted. Given the large range for an individual otter (35km for males and 20km for females), it can be difficult to determine presence or absence. Otters will also use different areas of their range at different times of the season dependent on water levels, food availability and riparian habitat requirements. For this reason, surveys are undertaken at different times of the year within the appropriate season and using a variety of techniques.
Survey techniques can include use of remote camera traps and a visual search for holts/couches, tracks (in mud and sand banks) and spraints (sites for droppings). Searching for spraints is one of the most frequently used techniques as otters will mark out their range with spraints on bridge arches, rocks, ledges, tree roosts etc. to protect their territory from other otters of the same sex (although otters of different sexes may overlap their range). Surveys are done multiple times over a year to cover different time periods and there should be at least five days without rain preceding the survey so that evidence is not washed away.
What an Otter Survey Includes:
A typical otter survey may involve:
Habitat assessment of watercourses and adjacent land to identify potential otter use areas
Search for field evidence such as spraints, footprints, runs, slides and holts
Mapping of key features and potential commuting routes
Assessment of potential impacts from proposed development works
Recommendations for mitigation or avoidance measures, as required
Survey scope is tailored to site characteristics and development context, providing relevant evidence for planning submissions.
Implications for development
If possible, any resting places (holts) of otters should not be disturbed during developments. If this is not possible, a European Protected Species licence will be required from Natural England and a detailed strategy of mitigation and compensation implemented. Ecosupport can create an appropriate Ecological Mitigation Plan for otters to inform your planning application.
Our experience with Otters
Our team has experience in surveying for otters and can undertake Phase II surveys and create a suitable mitigation strategy to get your site through the planning application without any issues.
FAQ’s
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Otter surveys are typically required where proposed works could affect watercourses, wetlands or riparian habitat. Even where no records exist, the presence of suitable habitat can trigger survey requirements.
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Otter surveys are most effective when carried out across multiple visits in conditions where evidence such as spraint, footprints, or holts is easier to detect, and survey effort is tailored to the site.
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If evidence of otter use is confirmed, mitigation measures may be required to avoid impacts. Our reports provide clear guidance on practical mitigation and, where necessary, the information needed to support licence applications.
Have more questions?