Abstract
The intended developments of offshore wind energy in the Dutch North Sea up to 2030 may lead to cumulative effects on seabird and/or migratory bird species, in terms of estimated numbers of collision victims. In the Framework for Assessing Ecological and Cumulative Effects (Dutch name for the framework: Kader Ecologie & Cumulatie; or in short KEC), the cumulative effects of all existing and planned Dutch and foreign wind farms in the southern North Sea are predicted and evaluated.
Given the potential negative effects of wind energy on the natural environment, the KEC includes several environmental impact assessments on the projected wind farms for the future. One of the focus areas in these assessments is the potential mortality of birds. As a result, within the KEC program, Waardenburg Ecology and Wageningen Marine Research are tasked with projecting the potential future mortality of birds due to (scenarios of) planned wind farms in the form of bird collisions (executed by Waardenburg Ecology) and habitat loss (executed by Wageningen Marine Research).
Since the first version of the KEC (Rijkswaterstaat 2015), the assessment has been updated several times (Rijkswaterstaat 2019, Potiek et al. 2022a, IJntema et al. 2025a). The next update (KEC 6.0) is planned for 2026. A new structure was introduced to increase the efficiency of KEC updates, which encompasses the execution of methodological improvements and data inventory during the year before the KEC update is carried out. Knowledge gained in 2025 will subsequently be used in the KEC 6.0 update.
This report presents the knowledge base update for the species relevant for collision mortality.