Otter Surveys

Otters & the Law

Otters are medium-sized semi-aquatic carnivorous mammals that live along rivers, lakes and coasts. Often mistaken for mink, they are larger, with brown fur and a pale underside. During the 1950s, otters suffered a significant decline as a result of the use of cyclodiene pesticides which bioaccumulated in the food chain (they mainly eat fish and amphibians). However populations have begun to recover in some areas and they can be spotted swimming and hunting in riparian habitats throughout the country.

Otters are fully protected under the Wildlife and Countryside Act (1981) (amended) and The Conservation of Habitats and Species Regulations (2017). This makes it an offence to kill or injure otters as well as disturb them or destroy their place of rest (i.e. habitat).

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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.

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

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.

About us

Providing quality ecology services across southern England and beyond since 1999.

At Ecosupport we complete comprehensive ecological reports for Preliminary Ecological Appraisals, Phase I Surveys, BREEAM, NVC Vegetation and Hedgerows and Phase II Surveys for protected species such as bats, reptiles, dormice, GCN, birds and badgers. We work directly with our clients to deliver pragmatic results and can implement any required mitigation or habitat restoration to see through your ecological needs from start to finish. Our large network of ecologists enables us to offer all our services all across the UK.

Ecosupport is SSIP-certified through SMAS Ltd.


Ecosupport - Head Office
K4 Keppel, Daedalus Park
Daedalus Drive, Lee-on-the-Solent
PO13 9FX


01329 832 841

Telephone (International)

+44 1329 832 841