Collision-related mortality was estimated using a collision rate model based on the stochastic Collision Risk Model
(sCRM, developed by Scottish Marine and Freswater Science). Bird numbers were based on density maps developed from counts from both ship-based and aerial surveys. Species-specific flight height distributions were created from GPS data, survey data and the literature. Species-specific characteristics (avoidance rate, flight speed, size) and wind turbine proterties (e.g. rotation speed, rotor diameter, maximum width, number of turbines) provide additional information in the estimates of collision rates.