Further Bat Survey

Methodology and timing

Emergence and aerial inspections of trees

Emergence surveys involve monitoring built-structures (and trees if aerial inspection is not possible) to assess whether bats are using features for roosting. The surveys involve monitoring Potential Roost Features (PRFs) identified during the Daytime Bat Walkover around dusk, using bat detectors and night vision camera equipment with infrared light sources or thermal imagery. Aerial inspection of trees involves searching at height during daylight for evidence of bats within all PRFs via roped access by CS38 qualified surveyors, ladders, or a Mobile Elevating Work Platform (MEWP).

The surveys aim to determine the number and species of bat using roost features, and to classify the type of roost/s present. This information will inform licensing and mitigation requirements.

Aerial inspections to confirm the presence of PRFs in trees can be undertaken at any time of year. If a built-structure or tree requires further surveys to determine presence / likely absence of roosting bats, emergencesurveys and aerial inspections can only be undertaken between May and September (inclusive). The majority of surveys should be within the peak activity season of between May and August (inclusive). Within this period, surveys should be separated by at least three weeks and usually preferably longer, as the way in which bats use roosts changes over the season. Depending on the potential of a built-structure or tree to support roosting bats, between one and three emergence surveys / aerial inspections will be completed. In some situations, more than three surveys may be required if needed to confidently classify a roost.

Night-time Bat Walkovers

Night-time Bat Walkovers (NBWs) can be used to determine whether or not changes in landscapes, such as hedgerow removal, construction of a wind turbine, installation of new lighting (e.g. road lighting) or an entire change of land use, will affect foraging and commuting bats. Surveyors monitor bat activity along potential flight-lines by walking transects around a site recording bat activity.Automated static bat detectors are also installed at specific fixed locations within a site, set to record all bat activity over a series of nights. These surveys aim to understand how bats use habitats on site to inform appropriate mitigation that will minimise the impact of the development on bats.

NBWs can only be undertaken between April and October (inclusive), with one survey per season (spring – April/May, summer – June/July/August, autumn – September/October) undertaken over this period. The quality of habitat for bats will determine the how frequently data should be collected using the static bat detectors.

Hibernation surveys

Hibernation surveys involve undertaking a close and systematic inspection of all potential roost features, with the aim to determine presence / likely absence of hibernating bats, their species, and the number of bats. The number of hibernation surveys is minimised to reduce the risk of disturbance to hibernating bats.

Hibernation surveys are undertaken throughout the hibernation period, November to March (inclusive). An automated static detector and temperature/humidly logger will be used to record bat activity between periods of torpor for at least two weeks each month between November and March. Inspections are usually undertaken between December and February, dependent on prevailing weather conditions and location, and must be conducted at least four weeks apart.

Autumn swarming surveys

Autumn swarming surveys involve recording bat activity at the potential swarming site using automated/static bat detectors. The bat detectors will be set to record bat activity between dusk and dawn, from 2 hours before until at least 5 hours after sunset. Autumn swarming surveys must be undertaken between mid-August and October inclusive. At least five nights of survey per month (in appropriate weather conditions) must be undertaken each month.

To request a more detailed bat survey information sheet, please email mail@emec-ecology.co.uk.

Report

We will provide a report detailing the survey methodology and results and providing an evaluation of the species recorded and recommendation for general mitigation measures, further surveys and/or consultation and licensing requirements, as appropriate. The report will be provided as soon as possible following completion of the surveys, however; should you have a specific date for submission of a planning application we will do our utmost to accommodate this.

EPS Licensing

When bat roosts are recorded, and will be affected by the proposed works, it is usually necessary to apply for a European Protected Species (EPS) licence from Natural England to allow works to progress. Should an EPS licence be required, EMEC Ecology can apply for this on your behalf. The EPS licence application requires the completion of a method statement, an EPS application form, works schedule, a  series of licensing plans and sometimes a reasoned statement in support of the application. The method statement will require site-specific mitigation to be designed. Full planning permission should be in place prior to application for an EPS licence.

EMEC Ecology is also able to undertake Natural England’s Low Impact Bat Licence applications where appropriate. This type of licence may be applicable where a roost is considered to be of low conservation significance (i.e. an individual or a small number of non-breeding bats of a common species).