Hundreds of bats could have been condemned to lingering deaths cemented into railway bridges by repairs that breached official guidelines.
Data obtained by The Ferret has revealed that most of the maintenance work carried out on Scotland’s rail viaducts in the last two years has failed to include recommended surveys for bats.
The surveys that have been done were insufficient to detect and protect colonies of roosting bats hiding in small holes high in the stonework. As a result large numbers of bats could have been missed and entombed as gaps were filled with mortar.
Wildlife groups and campaigners have reacted with alarm, calling on the government company responsible for the bridges, Network Rail, to do better. The company insisted that it was committed to minimising harm to wildlife, and promised to review its survey records.
Bats are highly protected under UK and European law as endangered species, and it is an offence to kill them. The penalties for destroying a bat roost include unlimited fines and six months in prison.
Bats roost within bridges and viaducts, often making use of cracks and crevices where mortar has fallen out. That’s why guidelines issued by the Bat Conservation Trust and backed by government wildlife agencies, including Scottish Natural Heritage, insist on comprehensive surveys before stonework is repaired and repointed.
Bat surveys of large structures should include “detailed visual inspections” by licensed experts, the guidelines say. Bridges high off the ground should be inspected using scaffolding, elevated platforms or climbing ropes, and ultrasonic surveys at dawn and dusk are suggested.
In response to repeated requests under freedom of information law, Network Rail has disclosed that it conducted “pointing repairs” on 27 of its 263 viaducts in Scotland in 2016 and 2017. But for 15 of them it had no information on bat surveys.
The 15 without survey data had potential sites for bat roosts. They included Ladyburn Street Viaduct in Greenock, St Enoch Viaduct in Glasgow, Cardenden Viaduct near Kirkcaldy and Dalguise Viaduct near Dunkeld.
Surveys were conducted before repairs to 12 viaducts in 2016 and 2017. But they were limited and involved mostly visual inspections from the ground, meaning colonies of bats could have been missed.
The figures were described as “very worrying” by the Bat Conservation Trust. “We are deeply concerned that proper steps, as set out by wildlife legislation, appear not to have been followed to protect potential bat roosts in viaducts,” said the trust’s conservation director, Dr Carol Williams.
“We would strongly urge greater transparency and collaboration by Network Rail in Scotland when it comes to consideration of bats in bridges.”
The trust assisted with a report published by the government in October 2018 highlighting similar problems facing bats and other wildlife during vegetation management by Network Rail in England and Wales. It has now offered to work with the company in Scotland to try and avoid harm to bats in the future.
Scottish Natural Heritage stressed the importance of not breaking the law on bats. Railway viaducts were “ideal habitat” with “excellent roosting opportunities” for bats, the government agency’s mammal specialist, Robert Raynor, pointed out.
“There is a wealth of experience and best practice guidance on how to detect signs of bats in bridges and viaducts, and how to retain access to bat roosts without risking the integrity of the structure,” he told The Ferret.
“If bat surveys are incomplete or don’t take place at all when essential maintenance is carried out, there is a risk that bat roosts and access points may be overlooked and then filled in during pointing works, potentially killing bats and destroying their roosts.”
Raynor added: “Both these actions are illegal without a licence, so we strongly urge following best practice guidance.”
The Glasgow Conservative MSP, Annie Wells, is the Scottish Parliament’s species champion for the common pipistrelle bat. “I hope that this will act as a wake-up call to many companies that these practices are simply unacceptable,” she said.
“I would encourage all companies to do all they can to follow legislative guidelines. It is hugely disappointing that this has not happened in this case.”
The Lothian Labour MSP and species champion for the noctule bat, Neil Findlay, thought the failure to protect bats was very concerning. “With any development we have to ensure the right steps are taken to protect wildlife, especially rare and protected species,” he said.
“Organisations like Network Rail have a duty to act and cannot ignore their responsibilities.”
The Scottish animal welfare charity, OneKind, was shocked by the “inconstancy” of Network Rail’s bat assessments. “Bats are a wonderful part of our wildlife and its unimaginable to think of them suffering, particularly when we know this could be easily avoided,” said director, Bob Elliot.
“There are tried and tested techniques that should be applied before work commences to avoid very real welfare issues occurring to any bats that may be hibernating, or in summer roosts in crevices or gaps in the mortar.”
He added: “Ensuring no bats are disturbed, killed or entombed when works are being carried out should be built in to inspection and repair regimes, and then these applied consistently at all sites.”
Susan Davies, conservation director at the Scottish Wildlife Trust, said: “It would be alarming if Network Rail is placing both bats and their roosts in danger by routinely cutting corners.”
It is Network Rail’s responsibility to ensure that contractors hired to repair bridges carry out surveys for bats. But because maintenance work doesn’t require planning permission, there are no independent checks.
When developments need planning consent, local authorities check whether bat surveys have been done and guidelines followed. This helps prevent bat roosts from being overlooked and accidentally damaged.
According to Network Rail’s website, the company looks out for bats. “We take care to look out for these special lineside neighbours,” it says.
Another page adds: “Our in-house ecologists work alongside external experts to carry out detailed surveys helping us to identify the animals, insects and plants in the area that might be affected by our railway maintenance and upgrade work.”
A Network Rail spokesperson said: “We are committed to minimising our impact on wildlife and are increasing the number of ecologists and environmental specialists within our business to help continually improve our processes.
“Our contractors should always be briefed to undertake surveys prior to significant structural works and we are reviewing our processes to ensure our records of surveys are accurately kept.”
Scotrail Alliance, which brings Network Rail together with the company that runs the trains in Scotland, Abellio ScotRail, declined to comment.
A Scottish Government spokesperson said: “The enforcement of the law is a matter for Police Scotland.”
- Bats have been around for 50 million years and have evolved into over 1000 different species worldwide.
- The rare giant golden-crowned flying fox from the Philippines feeds on fruit and has a wing span of 1.7m.
- The endangered bumblebee bat from the Philippines feeds on insects and is the smallest mammal in the world with a wingspan of just 170mm.
- There are nine species of bat known to breed in Scotland, including common pipistrelle, Daubenton’s, brown long-eared and noctule.
- Bats in Scotland are nocturnal and emerge from their daytime resting place, known as a roost, at dusk to hunt insects.
- Bats use a sophisticated systems of echoes to navigate in total darkness.
- Contrary to popular belief, bats are not blind but can see well in dim light.
- Bats roost in roof voids and tree cavities as well as in bridge crevices.
- In winter bats hibernate, sometimes at sites hidden deep in the brickwork of bridges.
- In summer female bats gather to form nursery roosts where they give birth to their young.
- All bats and their roosts are protected by law under the 1981 Wildlife and Countryside Act and the Nature Conservation (Scotland) Act 2004.
All the documents on bats and bridges released by Network Rail
A spreadsheet showing bridges, viaducts and pointing repairs in 2016 and 2017 can be downloaded here.