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Key Facts

Bat Presence / Absence Survey

Thank you for the opportunity to support your development ambitions.

Arbtech is widely acknowledged to be the leading ecological consultancy in the UK, specialising exclusively in arboriculture and ecology for planning and development sector clients.

Blowing our trumpet; we have been established since 2005 and since then we have been there, done that and got the t-shirts for just about any tree or protected species issue you could possibly face on a site of the proposed development.

To give you confidence in that statement, here are some metrics (as at Q4, 2022):

We now have over 60 team members, and all are directly employed consultants. Known internally as ‘Arbtechers’, they have done literally thousands of surveys over careers spanning in some cases decades, in both the public and private practice sectors. All are well versed in planning policy and wildlife law, as well as having developed good working relationships with the local authorities in their regions.

How do we leverage local relationships and yet offer fixed fees throughout the UK, Crown Dependencies and Ireland? We do this by having approximately half of our staff based at home in strategic locations. So, whether you’re in Sunderland or Southampton, we can cut costs and delays for you at a fixed, all-inclusive price.

If you would like to talk to someone about your development ambitions for your site, please do ask – it’s what we’re here for.

Why do I need an ecologist?

You have been asked to provide a report to your local authority to compliment your planning application because:

  • The NPPF states that when determining your planning application your local authority should aim to conserve and enhance biodiversity by applying the following principle; if significant harm resulting from your development cannot be avoided, adequately mitigated or compensated for then planning permission should be refused. (National Planning Policy Framework: p.174-188).
  • DEFRA Circular 01/05 sets out that the presence of protected species at your site is a material consideration and that it is essential that the presence or otherwise of protected species and the extent that they may be affected by your proposed development is established before the planning permission is granted. (DEFRA Circular 01/2005 Biodiversity and geological conservation – statutory obligations and their impact within the planning system: p.98 to p.99).
  • BS42020 is the British Standard for ecology, planning and development. It describes in detail the hierarchy of avoidance, mitigation, compensation and enhancement articulated in the NPPF. (British Standard BS42020 Biodiversity – Code of practice for planning and development (2013): p.6.2 detailing the adequacy of information to be submitted and p.6.13 on the need for composite reports to be submitted to draw together the conclusions of various ecological studies).

What is a bat presence/absence survey?

At this stage, I would like to save you time and money by recommending the minimum level of survey effort that is designed to satisfy your local planning authority’s ecologist.

As you can appreciate, most structures do not present high-quality habitat for bats, so only a small percentage of sites need anything other than a preliminary bat roost assessment (“PRA”). However, if you have requested a quote for a bat presence/absence survey, it is because your PRA (a physical inspection) has identified triggers for a further survey, such as bats, evidence of bat activity, eDNA evidence, or habitat value.

Therefore, we provide below a quotation for one of our Natural England licenced bat workers to visit you and undertake bat presence/absence surveys, compliant to the Bat Conservation Trust publication on survey standards and protocol ‘Bat Surveys – Good Practice Guidelines’. We have reviewed the available information about your site and are confident that this addresses your immediate needs.

Your bat presence/absence survey comprises several visits to your site between dusk and dawn, when bats are most active, for surveyors to use remote detection devices, which may include infra-red image capture and bat detection devices, and to physically observe any bats emerging from or re-entering features/apertures (there may be no emergences) that may be suitable for roosting.

Your local planning authority will expect us to be able to observe all elevations of your building simultaneously unless your PRA confirms that the roost is confined to one particular area. Consequently, several surveyors may need to be present on your site, with larger, more complex shaped buildings generally requiring a greater survey effort than e.g. a standard detached family home.

Finally, if you haven’t done so already (normally forms part of the preliminary roost assessment), our consultant will perform a desk study of local ecological receptors within 2km of your site (if any) and incorporate the results into your report.

There are then 2 possible outcomes, as follows:

What we found at your siteWhat this means for you
You do not have bats being observed and
recorded emerging from or re-entering your property.
Your planning permission can be progressed without delay.
You have bats. Bats were observed and recorded emerging from or re-entering your property.Your local authority may require you to submit a mitigation method statement as a condition of consent.
You will also need a European protected species licence.
Copyright © Arbtech Consulting Ltd 2021

Frequently Asked Questions

I’ve only been asked for the “bat survey” – do I really need Biological Records Data as well?

Yes. (If you haven’t already obtained it for your PRA).

Your local planning authority will expect to see biological records incorporated into the desk study element of your report. Without this valuable information, they will simply reject your report out of hand, because the methodology will not meet the minimum standard of survey defined by the Chartered Institute of Ecology and Environmental Management.

*Biological records are a data set that you or we must procure from your local provider; often your local authority themselves, or a wildlife trust.

Read more here: https://arbtech.co.uk/external-data-costs/

When can you do my survey?

Bat presence/absence surveys comprise multiple visits in the vast majority of cases, and it is worth noting that for scientific rigour these visits should be spaced at least 3 weeks apart (your local authority is unlikely to accept anything less). Finally, unless agreed otherwise, your report will normally follow within one week. Timescales for delivery of third party data or services may vary.

What site access do we need?

We need to access all the internal and external areas of your site, including any buildings, compounds and other structures, including loft spaces and any other voids. We will also need to make some ground-level assessments of any trees that may be impacted by your development proposals (if any).

How do I book?

Simply complete and return our Survey Booking Form along with your payment.

To make your booking as simple as possible, we accept most forms of debit and credit card, including American Express.

You can pay online or directly over the phone by calling one of our friendly administrative team on 01244 661170.

Do you charge mileage or other fees?

All our costs are inclusive of our time, travelling expenses and your report.


It is worth bearing in mind that British bats hibernate throughout the winter months when the insects on which they predate are less prevalent. To reduce the risk of a type II error (false-negative survey result), your local planning authority will expect to see that your bat presence/absence survey has been conducted between May and September.

Depending on your location, the climate, type of survey, and the sensitivity of the suspected roost, there may be an opportunity to relax these seasonal restrictions slightly (or they may need to be tightened up). We will confirm this to you at the time of your instruction.

Other factors to consider

Bat presence/absence surveys comprise multiple visits in the vast majority of cases, and it is worth noting that for scientific rigour these visits should be spaced at least 3 weeks apart (your local authority will not accept any less).

Finally, surveys should be undertaken on nights were the minimum temperature is not less than 10°C; there is no heavy rain; and where wind speeds are not too high.

Balancing Pragmatism and Science: survey at the extremes of the seasonal window

We are widely respected for our commitment to science, a strength that is leveraged to your benefit when your local authority’s planning officers assess our report. Therefore, at Arbtech, we work to the nationally accepted guidelines and standards by default.

However, we understand that there are many other pressures on any given project and therefore in some circumstances, it may be appropriate to discuss undertaking your survey in a more condensed timeframe than we have outlined above, assessed on a case-by-case basis by our Principal Ecologist and Bat Licence Lead – Natalie Evans.

In these instances, the client must accept that there is a risk that the survey could be regarded as sub-optimal by your local planning authority and/or the regulator, and that this may result in delays, refusal of consent, or their insistence upon a further survey effort in the following season.

At Artech, we firmly believe that guidelines are just exactly that: guidelines. We employ free-thinking scientists who are not slaves to these guidelines. Each situation is judged on the strength of its own merits and our consultants will attempt to help clients build a supporting case for sub-optimal surveys where there are other relevant factors that need to be considered.

The Company is highly aware of the difficulties that the survey guidelines cause to clients. We are not complacent about this and are carrying out independent research to examine the scientific validity of survey timings.

What happens next?

As soon as we have your booking information, you will receive an automated booking confirmation e-mail, followed by direct contact from one of our friendly ‘Arbtechers’ same or next working day, to arrange a mutually agreeable site appointment. This person will be your Project Manager and will be your primary point of contact for the duration of our engagement.

We hope that our Fixed Fee is met with your approval and look forward to working with you very soon.

Inevitably… the small print

This document and any e-mail, attachment, estimate or quotation is pursuant to our General Terms and Conditions (“Terms”): https://arbtech.co.uk/terms-conditions. The Terms give details of the basis upon which we will provide our consultancy services and should be read in conjunction with any accompanying correspondence.

Your fixed fee is based upon producing your report to version 1.1. This is a finalised report based upon a draft copy presented to you for your comments and approval. Any further iteration as a result of consultation with you or third parties may be chargeable.

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