New research by an ornithological trust has shown that high-flying birds are at greater risk of colliding with off-shore wind turbines.

The British Trust for Ornithology (BTO) has collated data from more than 30 studies to show that most seabirds fly near the surface of the sea, but some that typically fly higher will be at greater risk from turbines.

Many species, including puffins and arctic terns, fly at just five metres above the water's surface, while others, such as gulls, fly at 20 metres.

Alison Johnston, ecological statistician for the BTO, said the research revealed that more work needed to be done to look at how wind turbines were affecting marine birds.

'We hope it will be taken on board by industry and that it will encourage more research. It shows how little we understand about how birds use the marine environment and we need to know a lot more,' she said.

The studies used were produced by applicants as part of their plans for new offshore wind farms.

While the figures were based on research from around the UK, much of the data was based on applications from around the Norfolk coast, according to Dr Johnston.

The research suggests that building turbines higher above the sea or building a smaller number of large turbines, as opposed to many small ones, could reduce the number of collisions with birds.