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Turbines are threat to birds on migration, study finds

Birds of prey are at serious risk of crashing into offshore turbines as they migrate over open water, according to new research.

Scientists have discovered that unlike seabirds, which tend to avoid offshore structures, raptors such as hen harriers are attracted to the turbines by an “island effect”.

The study suggests that this may be because the birds are reluctant to cross open water and look for help while trying to navigate.

The findings come after it was announced last month that work is under way to construct parts for the £2.6 billion Beatrice Offshore Windfarm Limited (Bowl) project, in the Moray Firth.

A turbine’s blade can reach a height of 220m (752ft) which is around the same altitude at which the birds of prey fly over water.

Researchers at Aarhus University, Denmark, led by Henrik Skov, set up two bird finding radars and a laser rangefinder on a narrow strait on the Baltic Sea off the north coast of Germany during the autumn migration.

One of the radars was placed next to Nysted wind farm and the other placed further up the Danish west coast.

After watching the birds migration route, scientists spotted a large number of sparrowhawks, kites, harriers, buzzards and falcons flying through the sound.

The researchers found the the birds were deliberately making a beeline for the turbines and flying away from their normal route out of Scandinavia.

According to the study, the birds became more attracted to the structures as the head winds increased.

Writing in the Royal Society journal Biology Letters, the scientists suggested that the animals were trying seek shelter for bad weather. They said: “Birds are attracted to offshore structures for various reasons.“However, An ‘island effect’ similar to the process which causes attraction of land-bird species to small islands is perhaps the most likely driver behind the attraction behaviour.”

A spokesman for the RSPB responded to the new findings: “While we need to generate more electricity through renewable sources, this must be delivered in harmony with nature. “