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Otter & water vole scoping survey
An initial otter and water vole scoping survey is generally carried out as part of a Preliminary Ecological Appraisal. A desk top study is carried out to identify any records of otter or water vole close to site, with a field survey undertaken to record incidental evidence of otter or water vole presence, and assess onsite and adjacent habitats for their suitability to support these species.
This scoping survey can be carried out at any time of year, however a dedicated presence/absence otter or water vole survey may be recommended if habitat upon or adjacent a site is suitable to support either species and a proposed development or an activity is likely to have an impact upon these animals or the places they use for breeding, shelter or protection.
Presence/absence otter survey
An elusive, solitary and nocturnal animal, the otter is rarely seen during the day. A dedicated otter survey therefore involves searching for physical signs of otter activity such as otter droppings, known as spraints, feeding remains and prints as well as detailed mapping of bankside vegetation and adjacent habitats. A boat is sometimes used during these surveys.
Otters require clean watercourses with an abundant and varied supply of food, mainly fish and eels, as well as bankside vegetation offering secluded sites for their holts (covered breeding and nursing sites) and above-ground resting and grooming areas, sometimes called a couch.
Presence/absence water vole survey
A water vole is also a elusive animal rarely seen during the day. Therefore, a dedicated water vole survey involves measured inspections of the banks and associated habitats of any suitable watercourse/water body either on or adjacent site. The characteristics and significant features of the banks and any associated habitats are noted. Any field signs of water vole activity are recorded including actual water vole sightings, burrows, runs, latrines and feeding signs.
Water voles occur along waterways with a preference for slow flowing or still waters, and are often absent in areas were mink are present due to predation.
Timing of surveys
- Initial scoping surveys for these species can be undertaken at any time of the year as part of a Preliminary Ecological Appraisal.
- Otter surveys can be undertaken at any time of year, although vegetation cover and weather conditions may limit the times at which surveys can be successfully carried out.
- Water vole surveys ideally should be undertaken between March – September/October when animals are active and field signs of this species are likely to be more evident.
Mitigation and licencing
Mitigation for otter can take many forms and may include changes to a proposed site layout and day to day site practice. Creating buffer zones adjacent water courses to reduce disturbance, locating site compounds away from potential otter habitat, and avoiding night working involving flood lights and noisy machinery are just some examples. If an otter resting or breeding place e.g. otter holt, is to be disturbed by a proposed development or an activity, a European Protected Species Licence (EPSL) must be obtained.
Mitigation for water voles may include protection of watercourses where water voles are present in order to ensure that activities do not impact water vole habitat. If water vole habitat is to be destroyed e.g. destruction of burrows, then water voles will need to be removed from the area of works. This may be possible under a Natural England Class Licence to displace water vole out of the area of works, or alternatively a bespoke Natural England translocation licence may be required.
Legislation
Otters and their holts are fully protected under Schedule 5 of the 1981 Wildlife and Countryside Act (WCA) (as amended) and Schedule 2 of The Conservation of Habitats and Species Regulations 2017. This makes it an offence to kill, injure, capture or disturb otters or obstruct access to, or destroy their resting places in Britain.
Water voles are fully protected under Schedule 5 of the 1981 WCA(as amended). This makes it an offence to kill, injure, capture or disturb water voles or obstruct access to, or destroy their resting places in Britain.
Note
The above information is based on standard guidelines and current UK legislation. Every site is unique so please contact a Torc Ecology consultant who will advise on the best survey approach in relation to the project requirements.
Facts about otter!
The otter is one of the UK’s largest predators and an important biological indicator of the quality of our rivers and wetlands. Following a drastic decline in the 1950s throughout the UK and Europe as a combination of organopesticide introduction and habitat destruction, the otter was considered a priority species for conservation action. The phasing out of pesticides that caused the population decline, a significant improvement in river water quality with subsequent benefits to fish stocks, and introduced legal protection, has seen a gradual recovery of the otter population within the UK.
A natural expansion of remnant populations and the localised re-introduction of captive-bred and rehabilitated otters have seen otter numbers increase throughout most of England.
Otters feed mainly on fish and eels but will also take frogs, birds, small mammals, crustaceans and aquatic insects. In England otter cubs can be born at any time of year usually in litters of two or three. They can live up to 10 years old although the average age of a wild otter is generally between four-five years old.
Facts about water vole!
The water vole is the largest of the four UK vole species. Once one of the most common and widespread mammals in lowland Britain, the water vole has undergone a significant decline in numbers and distribution of any wild mammal in Britain during the 20th century with a 30% decline recorded between 2006 - 2015. A combination of predation from the introduced American mink, habitat loss, fragmentation and altered riparian management has contributed to this decline.
Water voles have been recorded eating 227 different plant species and need to eat 80% of their body weight every day (a water vole typically weighs between 140-350g). They can produce three - four litters of young every year. Water voles rarely survive two winters, the average age for a wild water vole being five months mainly due to predation.
