Bat Surveys

Preliminary Roost Assessments/Ground Level Roost Assessments

Preliminary Roost Assessments (PRA’s) and Ground Level Roost Assessments (GLRA) inspections are used to assess the suitability of structures and trees for roosting bats. The survey involves inspections of any buildings, structures and trees within the site to assess their potential for roosting bats by looking for suitable features or evidence of use by bats. These surveys will typically be included as part of a Preliminary Ecological Appraisal (PEA).

The results of these surveys will inform the need for any further bat surveys, such as nocturnal emergence/re-entry surveys or hibernation surveys.

Because of seasonal constraints associated with follow up surveys, it is recommended that you have a bat scoping assessment undertaken at the earliest possible stage to prevent delays.

Nocturnal Bat Surveys

If roosting potential has identified features suitable for summer roosting bats, further night-time surveys may be required in the summer to determine whether roosting or breeding bats are present. The surveys aim to identify:

Species present
Roost type
Numbers of individuals present.

These points are essential for obtaining a Natural England Licence which enables the development to proceed.

During the surveys, groups of a team of surveyors will observe the suitable features using infra-red technology and note any bats emerging or re-entering the features.

Between one to three night-time visits will be required. This varies based on suitability of the features and the risk of bats being present. These surveys can be undertaken between May-August with one of the surveys being possible in September (if multiple surveys are undertaken).

Bat Activity Surveys

Bat Activity Surveys aim to monitor how a site is utilised by bats and what species are present throughout the development site.

This is particularly important when ecological corridors are due to be impacted, such as hedgerows and woodlands, or where there will be significant increase in artificial lighting.

The surveys consist of walked transects and automated bat detector monitoring surveys.

Walked transects are generally undertaken on three occasions, throughout the bat season.

Automated bat detectors will be deployed across the site at key points to monitor activity levels for prolonged periods between April and October.

Tree Climbing Inspections

Tree Climbing Inspections, sometimes known as aerial inspections, can be undertaken at any time of year to assess a trees potential to support roosting bats (Please note, in some cases surveys will be recommended during the main bat activity season).

Tree climbing surveys can be a cost-effective method to survey trees as numerous trees can be climbed in a day and in many cases, features which may appear suitable from ground level, can be ruled out following a detailed inspection, therefore reducing the need for further surveys.

Tom Haley Ecology have an in-house team of Natural England Licenced Bat Surveyors, qualified to climb trees, making us well placed to support your project.

Bat Hibernation Surveys

If the bat scoping survey has identified features suitable for hibernating bats, further surveys may be required in the winter to determine whether hibernating bats are present.

The surveys aim to identify:

How are the features being utilised?
Species present.
Numbers of individuals present.