Seabirds in 3D: A framework to evaluate collision vulnerability with future offshore wind developments, Interim project report no. 1: Estimating collision vulnerability of the seabird community across a segment of the California Current System

For offshore wind turbines, the rotor swept zones (RSZ) typically start at 30 meters (m) and extend upwards by an additional 230 m. Collision vulnerability is greatest for birds flying at heights that overlap this zone, with the probability of collision influenced by seabird morphology, flight-style, and wind speed. This report presents a novel 3D Seabird Collision Vulnerability Framework (3D Framework) that integrates several decades of at-sea seabird observations and the offshore windscape to predict densities and vertical distribution of the 44 seabird species most widely encountered in at-sea surveys to allow a 3D perspective of what is expected below, versus at, RSZ-height.