Birds avoid turbines

Two new studies on the impact of wind energy generation on avian populations have demonstrated that wind turbines might not be the “bird killing machines” they are sometimes accused of being – and that birds are better at adapting to turbines than we think.

The two studies separately demonstrated that bird mortality from wind turbine collision is “orders of magnitude lower” than existing data have previously suggested, but also that birds actively change their behaviour to avoid operational wind turbines.

As reported by EuroNews over the weekend, the first study was commissioned by the German Offshore Wind Energy Association (BWO) and conducted by research and consulting firm BioConsult SH, analysing more than 4 million bird movements over a period of more than 18 months.

The second study, carried out by Swedish power company Vattenfall and Norwegian software company Spoor with analysis and reporting carried out by The Biodiversity Consultancy, recorded more than 137,000 birds during a 19-month period.

The German study used an artificial intelligence (AI) controlled bird radar system at Windtestfeld Nord, a wind turbine test site on the coast of Germany which hosts five different prototype turbines. The specialised cameras recorded the number of rotor transits – defined as birds crossing the rotor plane of the turbine – during four migratory seasons.

All told, the researchers analysed over four million bird movements over 18 months, combining digital data with on-site searches for bird carcasses, and found that migratory birds reliably avoided wind turbines.

Specifically, 99.87 per cent of birds approaching the turbines during the night and 99.86 per cent during the day avoided the turbines, resulting in collision risks of 0.0016 per cent and 0.0020 per cent, respectively. These results correlated closely with actual bird carcasses found at the sites, confirming the validity of the researchers’ collision risk models.