Apparently there are two colonies of voles: one is located directly in front of the shop, nestled beneath the fourteenth-century 'clapper' bridge, and the other is upstream in front of the Swan Hotel.
When people come into the shop and say they've seen a water vole I can't help asking them if they're sure that it wasn't a rat. It appears that people can be divided into two camps: those who see a small rodent in the river and call it a vole and those who see a small rodent in the river and call it a rat. Sort of half-a-glass full versus half-a-glass empty.
Sad to admit, I'm in the latter camp although I am told that these two colonies are in fact voles. They were nearly driven to exctinction by the mink which now itself has been eradicated, partly by another returnee, the otter. Leaving rats, sorry voles, aside, otters back and mink gone: even a half-glass empty sort of person like me is cheered by that.
Water Voles versus Rats: How to Tell the Difference