BATS and the places where they live are under threat.
And the Environment Agency in West Yorkshire is doing all it can to help protect the nocturnal creatures.
Officials are producing a factsheet to ensure that people planning maintenance or demolition work do not inadvertently destroy bat colonies.
Spokeswoman Bethany Marshall said: "Bats love to live under bridges - particularly those near rivers or streams - because the water provides a good source of insects for them to eat.
"But many people forget about them when carrying out maintenance work and the bats can find themselves trapped in the structure or homeless.
"We want to highlight the possibility that bats could be using structures such as bridges and culverts and say how to proceed if bats are found."
The information sheet, due out early next year, is aimed at applicants requesting an Environment Agency permit for work affecting watercourses, including bridges and culverts, or tree-felling.
Officials are helping to make it easier for people to look after local bats by supplying boxes for bats to live in.
They can also supply bat bricks, which have holes in them so the bats can fly in and out of structures.
Advice on any work in a river can be obtained by logging
on to www.environment-agency.gov.uk