About this time of year, water voles enjoy catkins laden with pollen; I think this is for the protein they offer. This vole at the bottom seems to have a particularly dense and fuzzy coat suggesting it's in good condition and ready for breeding.
This blog charts the fortunes of water voles in and around the Whitchurch area, North Shropshire. Water voles are one of the UK's most threatened mammals, extinct in many counties, and so it's vital they receive as much monitoring and protection as there is going. Here in Whitchurch we're lucky enough to have them right in the middle of town - how cool is that?