The nocturnal flights of migrating waterfowl and songbirds (passerines) were tracked by radar at the Utgrunden Lighthouse in southern Kalmar Sound on a total of 23 autumn and 26 spring nights from 2006 to 2008.
There are primarily three important questions regarding offshore wind turbines that this study was required to answer:
- Which flight altitudes do waterfowl use during their migration over open seas and at night as well as in conditions of poor visibility?
- How high do songbirds (passerines) fly over the sea at night and in conditions of poor visibility?
- How do both waterfowl and songbirds react under conditions of poor visibility when they come close to off-shore wind turbines?
An understanding of these matters is very important in order to calculate the risk of birds colliding with off-shore wind turbines. The knowledge can be used as a basis for planning, licensing and environmental impact assessments concerning offshore windparks.