Assessment of wind-farm and other bird casualties from cacasses found on a Northumbrian beach over an 11-year period

Capsule For 3748 bird carcasses found on 4.7 km of shoreline, the main cause of death was starvation. Three percent of deaths were attributed to wind turbines. Aims To assess the main mortality causes from bird bodies washed ashore near wind turbines built in 1993. Methods Weekly searches were made for bird carcasses to ascertain causes of death. Experiments tested the efficiency of searches, longevity of carcasses, and effects of wind direction on deposition rates. Results In total, 3748 bird carcasses were found, an average of 341 per year. Guillemots formed 24.3% of the total, Kittiwakes 9.7%, Herring Gulls 9.0%, Black-headed Gulls 7.4%, Great Black-backed Gulls 6.4% and Feral Pigeons 11.3%. Each year more carcasses were found in winter than in summer, with a nine-fold variation between winters. About 28.1% of carcasses were classed as starved, and 23.3% as eaten at sea (predation or scavenging). Of human-related causes, 3.3% were birds affected by fishing gear, 3.0% were oiled, 6.4% had died from collisions (including 3% with wind-turbines), the rest from minor or unidentified causes. Small passerines were probably under-represented. Conclusion Allowing for bodies not found, the local wind-farm probably killed 148.5-193.5 birds per year, or 16.5-21.5 birds per turbine per year (mainly large gulls).