Planned offshore wind farms near Bass Rock gannet colony could kill 1,500 birds a year - 12 times more than thought, study suggests
The world’s largest colony of gannets is under threat from proposed new offshore wind farms that could kill 1,500 birds a year, researchers have warned.
About 75,000 pairs of gannets, Britain's biggest seabird, breed on the Bass Rock in the Firth of Forth each year, nesting with such density that they give the rock its distinctive white appearance.
But two new wind farms planned nearby could threaten the colony, according to a new Government-funded study which found that gannets fly higher than had been thought – putting them at much greater risk of collision with turbine blades.
The likely gannet death toll from the wind farms could be up to 12 times higher than previous estimates suggested, the researchers from the universities of Leeds, Exeter and Glasgow said.
Gannets had been thought to fly well below the 22-metre minimum height above sea level of turbine blades, based on assessment by surveyors estimating heights by eye, or limited radar studies.
The new study, using tracking devices attached to birds’ tails, found that while they do fly at low heights when “commuting”, when actively searching for fish and diving the birds fly at typical heights of 27 metres.
The feeding grounds of the Bass Rock gannet colony overlap significantly with the planned wind farm sites, the study found.
The RSPB in Scotland is already bringing a legal challenge against the Scottish Government’s decision to grant planning consent for the wind farms, Neart na Gaoithe and Inch Cape, due to concerns about their proximity to seabird colonies.
Dr Ian Cleasby of the University of Exeter and lead author of the study, published in the Journal of Applied Ecology, said: "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 realised in the field – are high enough to cause concern over the potential long-term effects on population size."
Dr Ewan Wakefield, of the University of Glasgow, said: “Unfortunately, it seems that many gannets could fly at just the wrong heights in just the wrong places.” He called for the minimum height of blades above sea level to be increased to give the birds more “headroom”.
Wind industry figures tried to downplay the significance of the study, which was funded by the Department of Energy and Climate Change, pointing out that it was based on only 11 birds with trackers actually visited the proposed wind farm sites.
Hannah Smith, policy officer for Scottish Renewables, said: “It’s important to put this research into context. It focuses on developing a new method using a tiny sample of less than one percent of the total gannet population that can be found at the Bass Rock.
“Offshore wind farm developers in Scotland spend up to three years collecting detailed data on bird populations which is then scrutinised by various nature conservation bodies as part of their planning application.”