Voles live beside of rivers and canals. One of them was immortalised as Ratty in popular book The Wind in the Willows. Since the 1970s, however, voles in the UK have seen a 90% collapse in their numbers, caused by habitat loss and predation by mink. Surviving vole populations are often isolated from each other, leading to fears of their becoming inbred and suffering from a lack of genetic diversity.
A novel solution to this problem is being attempted with a vole colony in Hanwell, to the west of London. The voles live by a pond near to the Grand Union Canal, but they are unable to access the canal itself because of the high walls that form its boundary. The simple solution is to build ladders for the voles that will allow them to cross the canal bank and make their way to a special vole island that has been built for them. The further hope is that the furry rodents will then further explore along the canal.
If the trial is successful, the likelihood is that further vole ladders will be put in place across the UK, creating wooden superhighways to link up isolated populations.