How Long do Ecological Surveys Take?

One of the most common questions we are asked at the outset of a project is: how long do ecological surveys take?

The answer depends on several factors, including the type of survey required, the time of year, the scale of the development project and whether protected species are likely to be present. Some surveys can be completed within a few weeks. Others are seasonal and may influence your wider development plan.

Understanding likely timeframes early allows developers, architects and planning consultants to programme works realistically and avoid unnecessary delay with Local Planning Authorities.

Although the time of year is an important factor in the carrying out of many protected species assessments, there is no single timeframe for ecology surveys to span because each site is different. The duration of ecological assessment is influenced by:

• The habitats and species present (or with potential presence)
• The scale and type of development project
• Seasonal survey windows and optimal periods
• Local authority planning requirements
• Whether an Ecological Impact Assessment is required

A qualified ecologist will usually begin with a desk study and site visit to determine what level of survey effort is proportionate. In many cases, early clarity significantly reduces risk later in the planning process.

Most projects begin with a Preliminary Ecological Appraisal (PEA), sometimes referred to historically as a Phase 1 Habitat Survey.

A PEA includes a desk study and a walkover survey to identify habitats and any evidence of protected species. It assesses potential impacts and determines whether further targeted surveys are required.

Timeframe:

• Site survey: typically 1 day (depending on site size)
• Reporting: 1–2 weeks
• Total timeframe: usually 2–3 weeks from instruction

A PEA can be undertaken at any time of year, although spring and summer provide the most reliable habitat data. This flexibility makes it a useful starting point for most planning applications.

If the PEA identifies the potential presence of protected species, further surveys may be required. These are often the surveys that influence overall project timescales.

Bat Surveys

Bat surveys are seasonal. If a building or tree has roost potential, emergence and re-entry surveys must be undertaken during optimal periods (typically May to September).

• Preliminary Roost Assessment: can be done year-round
• Emergence surveys: May–September
• Multiple visits are often required
• Full process: 3–5 months, depending on season

If surveys are commissioned late in the summer, a project may need to wait until the following survey window.

Great Crested Newt Surveys

Where ponds are present on or near a development site, surveys for great crested newts may be required.

• Survey season: mid-March to mid-June
• Multiple survey visits required
• Environmental DNA (eDNA) testing can sometimes shorten the process

Depending on timing, this can add 2–3 months to a programme.

Barn Owl Surveys

Barn owl surveys are required where suitable nesting or roosting features are present, particularly in rural buildings.

Survey timing depends on breeding activity, but assessment can often be undertaken between spring and early autumn. A barn owl survey typically requires a site visit and reporting within a few weeks, provided seasonal constraints are met.

Other Species

Additional surveys may be required for reptiles, badgers, water voles or nesting birds, depending on site context and habitats. Each has its own ecology survey calendar and optimal periods.

This is why early ecological advice is so important; identifying constraints at the feasibility stage allows surveys to be built into the development plan rather than reacting to them later.

For larger schemes, an Ecological Impact Assessment (EcIA) may be required to accompany a planning application.

An EcIA draws together findings from all ecology surveys, assesses ecology impact and outlines mitigation, compensation and enhancement measures. It is typically required for larger or more complex development projects.

Timeframe:

• Dependent on completion of baseline surveys
• Reporting: 2–4 weeks once surveys are complete
• Overall duration: varies significantly depending on seasonal constraints

Where multiple protected species surveys are required, the EcIA programme will be driven by the longest seasonal survey window.

One of the most significant factors affecting how long ecological surveys take is seasonality. Many protected species can only be reliably surveyed during specific optimal periods.

Missing a survey window does not usually prevent development, but it can delay submission of a planning application until sufficient data is gathered.

For example, if bat surveys are identified in October, the next appropriate survey window may not open until the following May. That gap can affect land transactions, planning timetables and funding arrangements, forward planning is therefore critical.

In simple terms:

• Small sites with limited ecological constraints: 2–4 weeks
• Sites requiring seasonal protected species surveys: 3–6 months
• Larger schemes requiring full EcIA: 6 months or more depending on survey scope

Not every site requires lengthy survey work. In many cases, ecological constraints are minimal and can be addressed quickly. The key is establishing this early with a qualified ecologist who understands local planning authority expectations.

All ecological surveys should be undertaken by a suitably qualified ecologist, ideally a member of the Chartered Institute of Ecology and Environmental Management (CIEEM). Professional oversight ensures survey methods meet current guidance and that reports satisfy local authority validation requirements.

Early engagement with an ecology and environmental management specialist allows you to:

• Identify potential impacts at the feasibility stage
• Align surveys with optimal periods
• Reduce the risk of planning delays
• Integrate ecological mitigation and enhancement into design to support protected species and deliver proportionate solutions

Our director, Olivia Collington, is a chartered environmentalist and Natural England license holder for a wide range of protected species. With extensive experience leading ecology teams and delivering protected species surveys across the UK, she provides clear, pragmatic advice to support development projects, including Biodiversity Net Gain assessments.

At Collington Winter Environmental, we provide a full range of ecological surveys to support planning applications across the UK. From Preliminary Ecological Appraisals and protected species surveys to full Ecological Impact Assessment reporting, our advice is pragmatic and programme focused.

If you are asking how long ecological surveys take for your specific site, the most effective step is early review. We can assess likely requirements, advise on seasonal constraints and help you plan with confidence.

Contact Collington Winter Environmental today via info@collingtonwinter.co.uk or fill out the form below to discuss your development project and ensure ecological requirements are built into your programme from the outset.