Modelling and reviews

We are global leaders in citizen science and have expertise developing innovative systems to add value to data through high powered analysis and a strong modelling capability. Our track record includes supporting Environmental Impact Assessments (EIA) and Strategic Environmental Assessments (SEA) for large infrastructure projects, and we provide the specialist impact advice required to go through these processes. With their broad ranging interests and experience, our experienced team of scientists are also perfectly placed to carry out literature and data reviews on your behalf. 

Collision Risk Modelling

The Collision Risk Models (CRMs) used in estimating the number of birds that might collide with proposed wind farms are sensitive to a number of metrics, including the flux of birds entering the area of the wind farm, flight height of species, avoidance behaviour and flight heights. Working with industry and government, our work has improved the evidence base on these metrics, drawing data from multiple sources (boat surveys, digital aerial surveys, LiDAR, tracking) and examining how they are best incorporated in analytical models.

Case Study

Modelling distributions of birds at sea

As the number and size of offshore wind farms increase, novel technologies and innovative analytical approaches are needed in order to properly assess each project’s environmental impact. Working with Forewind Ltd, we combined data from boat and digital aerial surveys to produce robust models describing the spatio-temporal distribution of a range of sea bird species in the Dogger Bank Offshore Wind Farm Zone.

On behalf of The Crown Estate, we are working with partners to map spatial patterns in seabird flight heights, a key parameter in relation to assessing collision risk, using LiDAR data. Using bespoke analyses we aim to maximise the value of data collected using novel technologies.

Population Modelling

It is important to place predictions of the impacts associated with developments in context. There is a wide range of approaches to predict the population-level consequences of the impacts associated with wind farms. However, many of these approaches have been open to challenge, resulting in increased uncertainty and costs in the decision-making process. Building on our experience in avian demography and population modelling, we have been working with governmental advisors and regulators to develop robust methodologies for assessing the population-level impacts of wind farms, and other renewables, on bird populations.

Case Study

Understanding management actions

Our research is frequently applied to understanding the impacts of developments and land-use interventions on species and habitats. For example, UK estuaries are internationally important for waterbirds that rely on the high densities of invertebrate food species present. Oystercatchers on the Wash rely on cockles and mussels that are also harvested commercially. An analysis of the survival rates in relation to shellfish availability has helped develop a sustainable management strategy for the fishery.

Similarly, a study following displaced Redshank in the Cardiff Bay barrage development demonstrated a marked reduction in their survival. These two cases illustrate our rigorous, evidence-based approach.

Cumulative Effects

New developments cannot be considered in isolation because impacts are not restricted to one particular season. Additionally, migratory birds that cross multiple country borders can be at an increased risk compared to non-migratory species. For birds that range widely, individuals may be affected by a number of different wind energy installations, so the total risk of collision or displacement will be greater than for just the wind farm in question.

This is an extremely important consideration, as regulators require cumulative effects to be taken into account. However, as these can be difficult to determine and require a wider perspective, they have been relatively underreported in assessments. BTO Consulting utilises the BTO’s national bird monitoring data and large tracking datasets and are in an ideal position to develop new ways of assessing cumulative impacts.

BTO Consulting has a vision of a world in which nature conservation and sustainable development are founded on evidence-based decision-making, and in which society understands, values and contributes to that process. Dr James Pearce-Higgins, Director of Science 


By collecting and reviewing available evidence BTO Consulting is able to produce valuable synthesis and insights to inform management decisions. Examples of some of the many reviews we have undertaken include:

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