Voles are rodents related to lemmings and hamsters, but are generally stouter of body and have a longer, hairy tail, smaller ears too. They are sometimes known as meadow mice or field mice. Etymologically speaking, they were generically “field mice”, vole from Old Norse völlr, and related to wold/weald as parts of English place names.
Here, we have three species of what we call voles:
Microtus agrestis – the Field, or Short-tailed, Vole, there are an estimated 75 million
Myodes glareolus – the Bank Vole, estimated, 25 million
Arvicola amphibius – European Water Vole, sometimes incorrectly known as the water rat, it is not a rat, despite being called Ratty in The Wind in the Willows. Endangered species. Estimated 100000 individuals.
And, of course, there’s Microtus arvalis – Common Vole, present as a sub-species on Orkney (M. a. orcadensis) and in the Channel Islands, but not in England or Wales.
Distinguishing between the Water Vole and the three meadow voles is relatively easy. Separating Bank from Field is harder unless you can see the tail. The tail of the Field Vole is about 30% the length of its body, whereas that Bank Vole’s tail is much longer, about 50% the length of its body. If you can’t see the tail, there are other indicators, although none seem perfect.
The Bank Vole has a warmer, more rusty, colouration compared to the grey-brown of the Field Vole. The fur of the Field Vole is not quite so smooth and neat as that of the Bank Vole and also largely covers ears and nose, less so in Field Vole. All such indicators can be confused in the field especially when there are variants such as lighter, gingery Field Voles.
Habitat is not a good indicator either, as Field and Bank may well favour similar habitat despite their names. As with many vernacular species names, they can be spurious and based on folklore, pre-scientific observations, and whimsy.
I asked friends on BlueSky to weigh in on the photo above. Terry O’Connor sided with Bank Vole, which was my first thought on seeing it yesterday: “Chestnut with grey underfur looks right and its ears are on the big side for Field Vole.”
One of my biggest missed opportunities photographically speaking was to capture a shot of a Grey Heron gulping down a Water Vole while standing on the roadside verge along a local road bridge over one of our lodes.
I did get photos of a Bank Vole that was swimming across the river in front of the Earith car park at RSPB Ouse Fen. It was my definitely-amateur, but professional-seeming, togger friend Andy who first spotted it. It seemed to disappear at the water’s edge, but I spotted it again, sitting stock still in the water and we both got a few snapshots.