Services · Specialist

Otter Surveys

Otters are European Protected Species found on most UK river systems. If your development involves works on or near a watercourse, otter survey will establish whether holts, couches or regular sprainting sites could be affected.

Survey seasonYear-round
OptimalWinter (best spraint detection)
ProtectionEuropean Protected Species
MethodField signs survey

Overview

The Eurasian otter (Lutra lutra) has recovered strongly across most of the UK following its dramatic decline in the mid-twentieth century. Otters are now present on the majority of English river systems, including many in Sussex. They are strictly protected as a European Protected Species under the Conservation of Habitats and Species Regulations 2017, making it an offence to deliberately capture, kill or disturb otters, or to damage or destroy a breeding site or resting place (holt or couch).

Otter surveys are based on searching for field signs along watercourses and their margins: spraints (droppings, often deposited on prominent features), holts (underground resting places, typically under tree roots, rock piles or bankside cavities), couches (above-ground resting places), slides, footprints and feeding remains. Otters are largely nocturnal and rarely seen — field signs are the primary survey method.

Otters range widely (males may use 20+ km of river), so even a short stretch of watercourse on a development site may be within the territory of a resident otter. Where holts or couches will be affected by development, a European Protected Species licence from Natural England is required, supported by an impact assessment and mitigation strategy.

When you need this

  • Your development is on or near a river, stream, canal, ditch or lake
  • Bridge construction or repair, culvert installation or channel modification is proposed
  • Bank reinforcement or flood defence works are planned
  • Your PEA identifies watercourses where otters could be present
  • Lighting installation near watercourses that could affect otter behaviour

Our approach

  1. 01
    Desk study

    Review of biological records, local otter group data and Environment Agency records to establish the known otter status of the watercourse and surrounding area.

  2. 02
    Field signs survey

    A systematic search along both banks of the watercourse, typically 200–500 m upstream and downstream of the site, looking for spraints, holts, couches, slides, footprints and feeding remains.

  3. 03
    Holt and couch assessment

    Any potential holts or couches are assessed for activity, classified by type and mapped. Camera traps may be used to confirm activity at key features.

  4. 04
    Impact assessment and licensing

    Where otters are present and holts or couches will be affected, we prepare an impact assessment, design mitigation (artificial holts, timing restrictions, lighting design) and prepare the EPS licence application.

Frequently asked questions

01What is a spraint?+
A spraint is otter faeces — the primary field sign used in otter surveys. Fresh spraints have a distinctive sweet, musky smell (often compared to jasmine tea) and are deposited on prominent features like rocks, bridge footings and fallen logs at the water's edge. Their presence confirms otter activity in the area.
02What is the difference between a holt and a couch?+
A holt is an underground resting place — typically under tree roots, rock piles or in bankside cavities. A couch is an above-ground resting place, often a flattened area in dense vegetation. Both are legally protected as breeding sites and resting places under the Habitats Regulations.
03Can otters really be found in Sussex?+
Yes. Otters have recolonised most river systems in southern England, including the Arun, Adur, Ouse and their tributaries in Sussex. They are now a regular consideration for development projects near watercourses across the county.
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