In certain areas, bat and bird populations can be significantly effected by collisions with turbines or by experiencing sudden depressurisation immediately adjacent to the blade. "This is a major problem in the States, especially during the bats' migratory period," said Paul Racey, one of the University of Aberdeen team conducting the research. In an attempt to reduce this mortality rate, Racey and fellow scientist, Barry Nicholls, were funded by the People's Trust for Endangered Species to find a solution. Their testing shows that there is a significant reduction in bat activity when a portable radar beam is directed at their foraging sites.
Racey outlined three ways to deter bats using radar in a paper published recently in the journal PLoS One. One method employs a rotating antenna similar to those used in air traffic control – bats are known to avoid these large installations and the researchers hoped to replicate the effect with a smaller device. The team also tested a stationary antenna that used two different radar signals that used different pulse lengths.
His results showed that a fixed antenna was most effective at keeping the bats away. Radar signals led to a drop in bat activity of 38.6% in an area 30 metres from the device. The animals appeared to be unharmed by the experience and returned once the radar was switched off. With refinement and purpose-built radar transmitters, the effect could be even greater, said the researchers. "We want 80- 90% reduction in bat activity," said Racey.
Scientists are unsure why bats avoid radar signals. One explanation is that radar energy warms the bats' wings "like a kitchen microwave," said Racey. Another theory is that the bats' ears heat up, causing them to "hear" the radar signal as a clicking sound.
Commenting on these initial findings, Nida Al-Fulaij, Development Officer PTES says: "We are delighted that this important research is leading to practical conservation outcomes that will effectively protect bat populations.
The UK Department for Environment, Food and Rural Affairs has also recently commissioned a three-year study to gather data on the effect wind farms are having on bats in the UK.
For additional information:
