Offshore Wind Farms Threaten More Seabirds Than Previously Thought, Researchers Say

The UK is home to two-thirds of the world's northern Gannets, large white birds with yellowish heads and black-tipped wings that are considered a protected species. Researchers from the universities of Leeds, Exeter and Glasgow recently took a closer look at how closely these birds fly to nearby wind turbines and found that wind farms located within their feeding grounds could kill 12 times more gannets than previous studies estimated, according to a news release.

The minimum height for wind turbine blades is currenty approved at 22 meters above sea level, a height that researchers once thought was safely above gannet fly zones. But it turns out that during breeding season – between April and Septemeber in the UK – and when they have to fly to more distant feeding grounds, they inhabit the 27 meter zone and are at greater risk of flying into turbine blades.

The recent study, led by Professor Keith Hamer, of the School of Biology at Leeds, examined the largest colony of gannets living on the Bass Rock, which is an island along the outer part of the Firth of Forth in the east of Scotland. Roughly 70,000 breeding pairs live in this area. Gannet habitats are located only 50 kilometers from several planned offshore wind farms.

Currently wind power provides four percent of the UK's annual electricity. However, by 2020, this supply could increase to between eight and 10 percent, according to RenewableUK.

"Previous data had seriously underestimated the number of birds potentially at risk of colliding with turbine blades. 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," Dr. Ian Cleasby, lead author from the University of Exeter, said in a statement. "Our predictions suggest extra care be taken when designing and assessing new wind farms to reduce their impact on gannets."

Tiny GPS loggers were attached to gannets' tails, so researchers could track their flight from Bass Rock to their feeding grounds. They applied the data they collected to predictive models and found that roughly 1,500 breeding birds could be killed annually if they travel through two of the planned wind farms nearest Bass Rock.

Researchers suggest increasing the distance between the blade tips and the surface of the water, in order to give the seabirds more headroom. They believe that a new clearance minimum should be set at 30 meters above sea level, the release noted. 

Their findings were recently published in the Journal of Applied Ecology. 

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