As otters are highly mobile and wide-ranging, assessment of development impact on otters may need to take account of watercourses beyond the immediate development footprint. Surveying for evidence of otters includes:

• otter spraints (dung)
• otter footprints (tracks)
• feeding remains
• otter slides
• otter holts and couches.

Surveys can be undertaken at any time of the year, however spring is noted as the best time as evidence can be found more easily before summer vegetation growth.

Mitigation may involve working practices on site, the sensitive closure of otter holts at an appropriate time year or the incorporation of safe travel routes along watercourses passing under new roads and transport links.

Survey work should be undertaken if suitable habitat is to be impacted and is best undertaken from April- September. Survey work can be undertaken by walking banks or water channels. Water vole field signs include:

• Droppings and latrines
• Feeding stations
• Burrows, lawns around on-land burrows and above ground nests
• Footprints and runways in vegetation

It is always recommended that waterbodies and features containing water voles are retained and adequately buffered within any scheme. If this is not possible then appropriate mitigation will need to be agreed. This can involve displacement or translocation work undertaken under an appropriate Natural England licence.