Ecological Survey Season Calendar: A Guide to Survey Timing

Planning a development, land promotion, or renewable energy project?

Many ecological surveys can only be undertaken during specific times of the year. Missing the right survey window can mean waiting months for the next opportunity, potentially affecting your planning programme.

Start here: Survey timings vary depending on the species, habitat, site conditions and survey objectives, so the calendar is intended as a planning guide rather than a definitive list of survey requirements. Explore common ecological surveys and when they can typically be undertaken.

Download Calendar

Talk to an Ecologist

Woodland Condition Assessment

River Condition Assessment

Water Vole Surveys

Hazel Dormouse Footprint Tunnel Surveys

Hazel Dormouse Nest Tube Surveys

Great Crested Newt eDNA Surveys

Great Crested Newt Assessment Survey Season Diagram

Great Crested Newt
Population Size Class Assessments

Reptile Surveys

Badger Surveys

Bat Dawn / Dusk Surveys

Bat Hibernation Surveys

Bat Activity Surveys

Wintering Bird Surveys

Breeding Bird Surveys

Barn Owl Surveys

Avoiding Delays: Why Survey Timing Matters

Every site is different and not every development will require every survey, however, ecological surveys are often seasonal because they rely on detecting species when they are active, breeding, or visible. Commissioning ecology early means you can:

✔ Identify constraints early
Before land acquisition, design, or planning submission

✔ Avoid unnecessary redesign
Understand ecological constraints before plans become fixed

✔ Build a realistic programme
Allow time for seasonal surveys where they’re needed

✔ Keep advice proportionate
Understand which surveys your particular project actually requires

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Our approach is practical and commercially aware: We aim to identify the evidence your project genuinely needs, based upon the evidence on site and the impacts arising from your development, rather than recommending surveys for surveys sake.

What happens if you miss the survey window?

One of the biggest misconceptions we encounter is that ecological surveys can be completed whenever they are requested. Unfortunately, this isn’t always possible. For example:

Miss the bat activity survey season and further surveys may need to wait until the following spring.
Miss the reptile survey window and your programme could be delayed by several months.
Miss the optimum botanical survey period and habitat quality assessments may not be robust enough to support planning.

Early ecological input helps identify these requirements before they become a problem for your programme.

So, which surveys will your site actually need?

There isn’t a standard package of ecology surveys for every development. The appropriate surveys depend on the site, the habitats present, the proposed works and the potential for protected or priority species.

We will review site-specific factors such as:

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Protected species presence or potential presence

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Existing habitats

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The Proposed Development

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Local planning policy

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Biodiversity Net Gain requirements

For many projects, a Preliminary Ecological Appraisal (PEA) is a useful starting point. A PEA identifies likely ecological constraints and determines whether additional surveys are needed. Not every project needs every survey.

Learn more about Preliminary Ecological Appraisals →

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Preliminary Ecological Appraisal

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Frequently Asked Questions

Do all developments need ecology surveys?

Not always. The surveys required depend on the site’s habitats, location and the proposed development. A Preliminary Ecological Appraisal is usually the best starting point.

When should I contact an ecologist?

Ideally, you should contact an ecologist before purchasing land, preparing a planning application or commissioning detailed design work. It’s often best to get advice from an ecologist at the pre-app stage. Make sure to get the council’s ecologist to review the pre-app to get detailed ecological commentary on the proposal. Early advice helps avoid unnecessary delays.

Can surveys be carried out in winter?

Some can. Preliminary Ecological Appraisals, many habitat inspections and bat roost assessments can often be undertaken year-round, while other surveys have strict seasonal windows.

Can you help me work out which surveys my project needs?

Yes. We provide proportionate, site-specific advice based on your project rather than recommending unnecessary surveys.

Inside our free Ecology Survey Calendar

Download PDF Calendar

Inside you’ll find:

✓ Typical survey windows
✓ Key seasonal considerations
✓ Common protected species surveys
✓ Planning reminders

Useful for developers, land promoters, planners, architects and project managers.

A practical planning tool for development projects.

Planning a project?

Not sure which surveys you’ll need or when they should happen?

Talk to an Ecologist

Every project is different. If you’re unsure which ecological surveys your site requires, or when they should be commissioned, we’re happy to help.

Tell us a little about the location, proposed development, current planning stage, your timescales and any information you already have. We’ll help you establish the appropriate next steps.