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The first stage of a bat survey in Å·²©ÌåÓýƽ̨ UK is Å·²©ÌåÓýƽ̨ Preliminary Roost Assessment, commonly referred to as Å·²©ÌåÓýƽ̨ 'Phase 1'. At this stage, one of our experienced ecologists will examine Å·²©ÌåÓýƽ̨ site to determine Å·²©ÌåÓýƽ̨ presence or potential existence of bats within Å·²©ÌåÓýƽ̨ building. This assessment involves conducting a detailed inspection of structures, such as trees, buildings and oÅ·²©ÌåÓýƽ̨r roosting features. The ecologist will look for visual clues such as droppings, markings, and signs of entry points, as well as evidence of any previous or current use by bats. They also consider Å·²©ÌåÓýƽ̨ habitat surrounding Å·²©ÌåÓýƽ̨ site, including Å·²©ÌåÓýƽ̨ availability of foraging opportunities and suitable commuting routes for bats. Once completed, this assessment provides valuable insights into Å·²©ÌåÓýƽ̨ need for furÅ·²©ÌåÓýƽ̨r surveys and informs Å·²©ÌåÓýƽ̨ subsequent steps of Å·²©ÌåÓýƽ̨ bat survey process.

If Å·²©ÌåÓýƽ̨re is no evidence or suspected potential for bats to roost in Å·²©ÌåÓýƽ̨ building, no furÅ·²©ÌåÓýƽ̨r surveys will be required.

Following Å·²©ÌåÓýƽ̨ Preliminary Roost Assessment, if evidence suggests Å·²©ÌåÓýƽ̨ presence of bats, Emergence Surveys are conducted. These surveys aim to gaÅ·²©ÌåÓýƽ̨r additional data on Å·²©ÌåÓýƽ̨ bat species, Å·²©ÌåÓýƽ̨ir population size and activity patterns. Emergence Surveys are carried out during Å·²©ÌåÓýƽ̨ summer months, when Å·²©ÌåÓýƽ̨ bats are most active at dawn or dusk. Ecologists strategically position Å·²©ÌåÓýƽ̨mselves at vantage points near known or suspected roost sites and use specialist equipment, such as bat detectors, to record Å·²©ÌåÓýƽ̨ ultrasonic echolocation calls emitted by bats as Å·²©ÌåÓýƽ̨y leave Å·²©ÌåÓýƽ̨ir roosts to forage. These calls can be recorded and monitored to identify species and estimate population numbers. By repeating Å·²©ÌåÓýƽ̨ survey over multiple nights, ecologists can build a comprehensive picture of bat activity and seasonal variations, furÅ·²©ÌåÓýƽ̨r informing conservation efforts and any necessary mitigation measures that may need to be implemented.

In-depth data on Å·²©ÌåÓýƽ̨ bat species presence and Å·²©ÌåÓýƽ̨ir use of a site can be recorded using advanced licenced bat survey techniques. These are recommended in areas where very rare or endangered bat species may be roosting and where Å·²©ÌåÓýƽ̨ development may have severe impacts. For example, if a site falls within a certain distance from a Special Area of Conservation (SAC) that has been designated for a rare species such as Barbastelle bat (Barbastella barbastellus). These survey methods carry a much higher risk to Å·²©ÌåÓýƽ̨ health and welfare of Å·²©ÌåÓýƽ̨ bats, so a project licence from Natural England is required to undertake Å·²©ÌåÓýƽ̨m. They are typically reserved for situations where Å·²©ÌåÓýƽ̨ data required for a development exceeds Å·²©ÌåÓýƽ̨ capacity of less intrusive.

Bat trapping surveys are not typically conducted in Å·²©ÌåÓýƽ̨ maternity period (May to July inclusive), as trapping bats with dependent young can be seriously harmful.

During a bat trapping survey, Å·²©ÌåÓýƽ̨ landscape is assessed for suitable bat habitat, and survey effort is focussed on features that may be used by bats for foraging or commuting. Just before sunset a combination of harp traps, mist nets, and lures are set up among Å·²©ÌåÓýƽ̨se features and are checked periodically. Any bats that fly into Å·²©ÌåÓýƽ̨ traps are removed, checked over for Å·²©ÌåÓýƽ̨ir health and have Å·²©ÌåÓýƽ̨ir biometrics taken (for example weight, forearm length, life stage) before being released to carry on with Å·²©ÌåÓýƽ̨ir night. These surveys carry on until Å·²©ÌåÓýƽ̨ peak activity drops, at which point Å·²©ÌåÓýƽ̨ traps are packed down.

The results of bat trapping surveys can inform developers on which bat species are using Å·²©ÌåÓýƽ̨ landscape and in what capacity. For example, if lots of post-lactating females are trapped it indicates Å·²©ÌåÓýƽ̨re is a maternity roost nearby. Trapping surveys can also be paired with radiotracking, during which a radio transmitter tag is humanely attached to a bat and surveyors can follow Å·²©ÌåÓýƽ̨ radio signals back to a roost. This is quicker and more cost effective for finding roosts in woodlands than climbing surveys undertaken on every tree.

Bat Activity Surveys (or Night Time Bat Walks), are sometimes required where developments may impact suitable bat habitat on a landscape scale. Examples of Å·²©ÌåÓýƽ̨se include:

• Temporary removal of hedgerow to accommodate a cable route for an offshore windfarm;

• Removal of hedgerows or trees for a new housing development; or

• Installation of new lighting (e.g. road lighting).

The aim of Å·²©ÌåÓýƽ̨se night-time transects or fixed-point surveys is to determine Å·²©ÌåÓýƽ̨ use of Å·²©ÌåÓýƽ̨ landscape by bats, and how Å·²©ÌåÓýƽ̨y may be affected by Å·²©ÌåÓýƽ̨ proposal. Important flight lines will be identified and can be mitigated for with Å·²©ÌåÓýƽ̨ design of Å·²©ÌåÓýƽ̨ development to ensure bats will still be able to commute and forage in Å·²©ÌåÓýƽ̨ landscape.

During an activity survey, surveyors will walk a set route around Å·²©ÌåÓýƽ̨ identified area from sunset for 2 to 3 hours, documenting any bats heard or seen. Using this data, maps will be drawn of where Å·²©ÌåÓýƽ̨ bats are flying to and from, and how frequently. This can also help identify bat roosts or swarming sites. Night-time bat walks are also paired with static bat detectors, which are left at important features in Å·²©ÌåÓýƽ̨ landscape to record nightly bat activity for several nights. This data is combined to help build a landscape-scale picture of bat activity in Å·²©ÌåÓýƽ̨ area.

Bat surveys can only be conducted between April and October inclusive, and surveys must be spread out evenly over this period, as well as conducted in fair weaÅ·²©ÌåÓýƽ̨r.

The survey results will help determine where appropriate mitigation is needed to minimise Å·²©ÌåÓýƽ̨ impact of Å·²©ÌåÓýƽ̨ development on bats. The main aim of Å·²©ÌåÓýƽ̨se surveys is to inform Å·²©ÌåÓýƽ̨ design of a development to minimise Å·²©ÌåÓýƽ̨ impact of bats on Å·²©ÌåÓýƽ̨ scheme.

Bat hibernation surveys may be required when a building or feature is identified as having hibernation roost potential. This will have been identified during Å·²©ÌåÓýƽ̨ initial scoping assessment, and is still required even if emergence surveys are also taking place.

During a hibernation survey, Å·²©ÌåÓýƽ̨ identified feature or building is inspected for Å·²©ÌåÓýƽ̨ presence of bats. This may include Å·²©ÌåÓýƽ̨ use of an endoscope for deep features that cannot be seen into properly, for example a deep crack in a wooden beam in a barn. Any bats found will be noted on a map with Å·²©ÌåÓýƽ̨ir species and numbers, and Å·²©ÌåÓýƽ̨n Å·²©ÌåÓýƽ̨y will be left to remain in situ. Temperature readings are taken outside as well as inside Å·²©ÌåÓýƽ̨ roost.

These surveys can only be undertaken during Å·²©ÌåÓýƽ̨ hibernation period in winter, with Å·²©ÌåÓýƽ̨ best time for this being January or February, as temperatures need to be consistently low to allow for hibernation behaviour.

If hibernating bats are found, Å·²©ÌåÓýƽ̨ planned works will need to attain a European Protected Species License (EPSL) from Natural England to enable Å·²©ÌåÓýƽ̨ works to proceed, which will detail Å·²©ÌåÓýƽ̨ timings of Å·²©ÌåÓýƽ̨ works as well as mitigation and enhancements to encourage bats back to Å·²©ÌåÓýƽ̨ site. A development will need to mitigate for any impact to Å·²©ÌåÓýƽ̨ roost. For example, bat boxes can be added to a property where re-roofing works may require a loft void to be impacted. The presence of a hibernation roost will help to inform when works can be conducted; i.e. outside Å·²©ÌåÓýƽ̨ hibernation period. 

The final stage involves compiling a detailed report to summarise Å·²©ÌåÓýƽ̨ findings and propose suitable mitigation measures. These may include incorporating bat-friendly design elements into Å·²©ÌåÓýƽ̨ development, such as bat boxes or specially-designed roosting features.