Despite the studies conducted on environmental risks on wind farms, little has been studied using the actual offshore sites. In addition, the study focuses primarily on water birds, but would like to research from pre-construction to initial operation (factor of 4.5). However, only 0.9% of day flocks and 0.6% of night flocks flew close enough to the turbines to pose any danger. More birds fly by the turbines at night as compared to the daytime, but counteract this by maintaining a safer distance. Overall, the population of birds at risk for turbine collision is less than 1%.
The study was conducted at the Nysted offshore wind farm south of Denmark. The species studied were the common eider and geese. In order to estimate flight patterns, researchers used surveillance radar. The data finds that birds fly closer to the turbines during the day than at night, but the birds place more distance between themselves and the turbines at night. Complimentary studies are needed to confirm findings.