They’re designed to make sure bats don’t get killed by the traffic rushing along busy new roads.
But the 15 ‘bat bridges’ that have been built across the UK from Cumbria to Cornwall at a cost of £2million simply don’t work, say scientists.
These wire structures (or gantries) are meant to fool bats that use echolocation to navigate, so they think there’s a tree canopy blocking their path, causing them higher.
But Dr Anna Berthinussen, a bat ecologist commissioned by the Government to study the bridges said: ‘The evidence suggests that actually no, these structures are not effective, they’re not meeting their purpose.’
Dr Anna Berthinussen, a bat ecologist commissioned by the Government to study the bridges said: ‘The evidence suggests that actually no, these structures are not effective, they’re not meeting their purpose.’ Pictured: A bat bridge in Norwich
Dr William Sutherland, who runs the National Conservation Evidence Database at Cambridge University, added: ‘Wire bat bridges, or gantries, have been created in many locations costing about £2million. Pictured: A bat bridge crossing the A590 dual carriageway, Cumbria
Dr William Sutherland, who runs the National Conservation Evidence Database at Cambridge University, added: ‘Wire bat bridges, or gantries, have been created in many locations costing about £2million. Before and after tests showed they were ineffective.’ He told BBC’s Countryfile: ‘We have good ideas, but the good ideas get turned into best practice without there being testing in between.
‘And that’s where the problem is. It’s just based on faith rather than science.’
Dr Berthinussen’s study focused on seven of the bridges which were built across the Norwich Northern Distributor Road at a cost of around £1million to prevent disturbance to ‘nationally significant’ populations of Barbastelle bats – the UK’s rarest species.
Ninety percent of bats had to be flying within five meters of the bat bridge. Pictured: Lesser horseshoe bat (file image)
A safe distance of five metres from the bat bridge should have allowed ninety percent of bats to fly at least 90 per cent. However, the study showed that 40% were crossing unsafely high heights.
Norfolk County Council said: ‘Until several more survey seasons have been completed it is not appropriate to draw any conclusions about the effectiveness of the gantries.’
According to the Environment Act, new roads are required to minimize wildlife-related impacts. The noise of traffic lights and the light pollution on country roads disorientate bats.