Bat flaps used to help clear Galashiels railway tunnel
A series of one-way flaps and pipes have been fitted to a Victorian rail tunnel in the Borders to enable bats to leave ahead of renovation works.
The operation was necessary after a small group of the animals was discovered near Galashiels.
A multi-million pound project is currently under way to reopen a rail link between the Borders and Edinburgh.
The work to let the bats leave the 165-year-old tunnel was carried out under licence from Scottish Natural Heritage.
Although no breeding or hibernation roosts were discovered in the tunnel, some Soprano pipistrelle and Myotis bats were found to be temporarily living in spaces such as those which were once used by railway workers seeking safety from passing trains.
Now the one-way devices have been put in place to allow the bats to move out.
A small number are already using bat boxes which have been installed in nearby trees to provide alternative roost sites.
Ecologist Reuben Singleton, working with IKM Consulting, said: "Our initial surveys showed that a small number of bats were leaving the tunnel at dusk and re-entering it at dawn.
"Further investigation revealed a number of small cavities in the tunnel where bats could be roosting.
"On these cavities we installed temporary excluders and waited for the bats to leave."
He said they would continue to monitor the tunnel for activity but that the methods used should "substantially reduce the risk to bats from the works".
"We expect that the bats will continue to use the alternative roost sites provided," he added.
Network Rail's project director Hugh Wark said it was "committed to protecting local species as works progress".
"Sometimes this means relocating local wildlife, and in doing so, it is essential that we work with ecology experts to do this correctly," he said.