In order to minimise disruption to landscape and nature, infrastructure projects must carry out seasonal site surveys within strict calendar windows – miss one and a scheme could be delayed by up to 12 months.
Infrastructure projects, while run on commercial timelines, are deeply tied to the land and the wildlife occupying it. All projects need to take seasonality into account in relation to negotiating access, securing surveys or co-ordinating works.
Ecological survey requirements in England are governed by a tight regulatory framework including, but not limited to, the Wildlife and Countryside Act 1981, the Conservation of Habitats and Species Regulations 2017, Natural England guidelines and Chartered Institute of Ecology and Environmental Management survey guidelines. This framework dictates the timing and method of the various surveys required for the planning process.
What are the requirements?
As we move through the seasons, there will be obvious changes to project scheduling to account for varying survey requirements. This has both a practical and legal element.
The time of year affects wildlife behaviour which directly affects their visibility. Miss a window of activity and the resulting data may be harmfully skewed. Legally, disturbing nesting birds or interfering with protected habitats during sensitive periods can constitute a criminal offence.
For land consents and survey co-ordination teams, this means access agreements must be structured around ecological timing, not the other way around.
The following are examples of seasonal windows that will impact site activity:
- Great crested newt traditional surveys: mid-March to mid-June
- Bat activity surveys: May to September
- Botanical surveys: May to August
- Breeding bird surveys: March to July
Some surveys, such as Preliminary Ecological Appraisals (PEAs) and desk studies, can be undertaken year-round. These are invaluable early-stage tools because they identify which seasonal surveys will be required and help shape access strategies with landowners.
It is clear from the above that spring and summer bring an increase in survey requirements and, in addition to these seasonal restrictions, there are also weather-related access constraints that see the warmer months as the green light for much of the required survey activity.
For example:
Weather-related restrictions
- Waterlogged fields can prevent ground investigation works or make access unsafe
- Peatland and moorland may be inaccessible in winter due to conservation restrictions
- High fire risk on heathland in summer can limit survey and construction activity
Agricultural land access
- Crop growth can obscure visibility for botanical surveys or make transects (a prescribed path used by land surveyors while carrying out ecology surveys) impossible
- Landowners may restrict access during harvest, lambing or other significant times in the farming calendar
Agricultural cycles in particular can clash directly with survey windows, therefore appropriate co-ordination is essential.
What is the impact of survey delays?
Survey delays impact more than just scheduling and cost estimates due to the data requirements for planning and project development.
Seasonality is deeply embedded into the planning system which requires seasonally valid data for Environmental Impact Assessments. Natural England will not issue protected species licences without appropriate seasonal evidence. Surveys that have been previously completed, even if under the same project, may require repeating if they are more than two to three years old which also brings a forward-planning element in addition to the seasonal scheduling restrictions.
Missing a survey window can trigger a domino effect across a project. Delays in securing access or gathering necessary data can push back design freeze/project milestones, mitigation planning, construction sequencing and landowner negotiations. These issues not only have financial and developmental implications but also have a direct impact on the landowners involved with these infrastructure projects, prolonging the period of disruption.
Aligning human timelines with ecological realities
Seasonality is not a bureaucratic hurdle, it is a biological and practical necessity – and understanding the constraints is essential to securing access, maintaining landowner relationships and keeping infrastructure projects on track.
The message here is simple: co-ordination is key. Careful management of both regulatory timelines and landowner requirements is an essential first step for all infrastructure projects and sets a tone for successful delivery and stakeholder relationships.
Further information
Contact Ellie Crawley
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