Offshore Wind a Threat to Gannets?

With about four percent of its population using offshore wind power, the U.K. is arguably the world leader in clean energy. But a new study suggests that the U.K.’s aims to harness renewable energy could have an unintended negative environmental impact. 

Researchers at the universities of Leeds, Exter and Glasgow have released a study suggesting that offshore wind farms could pose a greater threat to Scotland’s gannet population than previously thought. The U.K. is home to more than two-thirds of the world’s gannets. 

It was previously believed that gannets, which breed in the U.K. between April and September, generally flew below the minimum height of 22 meters above sea level swept by the blades of offshore wind turbines. 
However, the researchers estimate that up to 12 times as many gannets could be killed by turbines than previous studies suggest. 

The joint study, which was led by University of Leeds Biology Professor Keith Hamer, shows that gannets often fly at an average height of 27 meters above sea level when hunting and diving for prey. In addition, the study revealed that the planned wind farm sites in the Firth of Forth, a Scotland estuary which flows into the U.K. North Sea, are located in feeding grounds used by more than 140,000 gannets. 

"Previous data had seriously underestimated the number of birds potentially at risk of colliding with turbine blades,” said University of Exeter Professor Dr Ian Cleasby. “There's a lot of uncertainty over how many birds would actually be killed this way, but our predictions – if realized in the field – are high enough to cause concern over the potential long-term effects on population size.”

Gannet flight height data was previously obtained by eye or using radar. Both of these methods had limited ranges, and environmentalists have long called for improved methods of risk assessment. 

The university study used data from GPS loggers and barometric pressure loggers to provide estimates of collision risk. The study documented gannets’ foraging ranges, densities of birds at sea and their flight heights during different activities. The collected data was then used to create collision-risk models to predict the likelihood of birds colliding with turbines.  

With several offshore wind farms in the pipeline in the foreseeable future, it is unclear what impact, if any, this research could have on the budding industry. The early response from offshore wind industry officials is that the

study was limited in scope because it did not study a large enough sample size of gannets.

Click here to read the full study.