Abstract
In the Netherlands, offshore wind energy is considered a key sector to facilitate the transition to green energy and continuous growth of the sector is intended by the government. Offshore wind energy, however, is not without effects on the natural environment and marine life. One of the species groups impacted by wind energy developments is birds, specifically local seabirds and birds migrating over sea. In the Netherlands, in the Framework for Assessing Ecological and Cumulative Effects (in Dutch: ‘Kader Ecologie & Cumulatie”; abbreviated to KEC) the expected impacts on different species groups, including birds, of existing and planned wind farms are assessed in cumulation for the Dutch Continental Shelf in the North Sea. The effects currently specifically assessed within KEC are displacement (Soudijn et al. 2025) and collisions (IJntema et al. 2025). However, an often mentioned, rarely assessed, third effect is barrier effects (Drewitt & Langston 2006). In the most recent version of the KEC (5.0), barrier effects are not specifically assessed.