To see whether the 13,000 offshore turbines planned for European waters would be a hazard to migrating birds, Mark Desholm and Johnny Kahlert of the National Environmental Research Institute in Rønde, Denmark, used radar to track flocks of geese and eider ducks around the Nysted wind farm in the Baltic Sea. The farm's 72 turbines are laid out in rows with their blades 480 metres apart.
Desholm and Kahlert found that the birds flew almost exclusively down the corridors between the turbines, with less than 1 per cent getting close enough to risk collision. The birds gave the turbines an even wider berth at night, sticking more closely to the middle of the corridors. Many also avoided the wind farm altogether. The researchers found that while 40 per cent of flocks in the survey area crossed the wind farm site before construction started, only 9 per cent ventured among the turbines once they were operating (Biology Letters, DOI: 10.1098/rsbl.2005.0336).
Source: Erickson, et.al, 2002. Summary of Anthropogenic Causes of Bird Mortality. A study done in the US; at the time, there was 4.5 GW installed, and a few eighties parks, especially Altamont Pass, were responsible for most birdkills. So even if wind is developed in the extent I calculated in reply to asdf (i.e. a 400-fold increase on 2002), birdkills will stay below that of any other significant causes. *Lunatic*, n. One whose delusions are out of fashion.
