Seabirds spend a significant portion of their time at sea, where they are vulnerable to impacts from marine energy infrastructure such as offshore windfarms. Therefore, it is essential that the potential risks to seabird populations, either through collision with turbines or displacement from important foraging areas, are assessed prior to development. Very little is known about the vulnerability of seabirds to offshore windfarms in Irish waters. Seabird vulnerability indices have been

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... as part of the biological component of EirWind Work Package 4 through updating previously published indices in an Irish context, incorporating new data, and accounting for advances in turbine technology. Two Collision Vulnerability Indices were calculated, one accounting for a turbine sweep zone starting at 20 m above sea level, and one accounting for a turbine sweep zone starting at 40 m above sea level. Collision vulnerability was generally lower for all species in the 40 m index compared to the 20 m index, indicating that if larger turbines are installed in Irish waters overall collision risk could be lower than previously expected. A separate Displacement Vulnerability Index (DVI) was produced to assess population level vulnerability to displacement from important habitats due to the siting of offshore wind developments. Generally, species with a high DVI score (e.g. divers and auks) had low CVI scores. Conversely, shearwaters and storm petrels had the lowest DVI scores but high CVI scores. All vulnerability index scores were applied to seabird distributions in the Irish Sea. These show a distinction between the areas of highest vulnerability for collision susceptible species and displacement susceptible species, particularly in the summer. Therefore, species and risk factors will vary by site and season. The Vulnerability scores (CVI and DVI) will be applied to seabird distribution data covering the entire Irish EEZ in Deliverable D4.14 due at the end of December.