Bat Bridges, or why deleting lonely tags is a bad idea

The other day I was idly browsing the blog of Mark Avery, the former conservation director of the British bird protection society, the RSPB. One item caught my attention: it was about 'bat bridges'. Although I hadn't heard of them before it was pretty obvious what they might be.

A bat bridge on the A590 in Cumbria

Bats tend to follow linear features in the landscape when foraging at night, at least in part because they provide protection from predators. Bats tend to avoid flying over open spaces. Hedgerows, edges of woods, and so on, form commuting routes between roosting and feeding sites for bats. When these are damaged or destroyed, for instance by road building, bats either lose feeding locations or have to cross the open space. Usually they do this by flying low: effective against their age-old predators, but not much help when confronted by a car.