The Water Vole and the Folk Festival

I was cycling along  Cherryhinton brook one afternoon last week and heard the music from the Folk Festival drifting over the alotments, a nice lilting melody mixing with the sounds of nature all around. As I rounded one of the bends in the footpath I noticed a little water vole sitting mesmerised on a patch of Greater pond sedge (Carex riparia) .  I am sure it was feeling just as mellow as I was. It knew I was watching but went about its nibbling for some moments. Then plunged into the water and dived down to the bottom of the stream. A great cloud of mud billowed up as the vole started an excavation process. It was digging at the base of the sedge plant and eventually resurfaced with a length of white succulent rhizome in its mouth. It then resumed its meal and had soon consumed this prized moursel. I imagine the rhizomes must contain lots of stored starch, so the vole was getting a much better meal than it gets from endless nibbling of the leaves.  It was a very young vole and quite small, so I wonder how it learnt to expertly dive and excavate in this way so early in its life. Presumably by watching its parents.
I have discovered that if you want to see a water vole, the easiest way of spotting them is to look out for unusual ripples on the water surface. The voles sit under the bank and nibble food. The frequency of their nibbling is much faster than other animals, so the ripples they produce are a shorter wave length than say a moorhen or a mallard, which are also found along the brook. I think the ripples come from the vibration of their tummies as they nibble. They are very enthusiastic nibblers and they are always eating. I can often find the hidden voles right in the middle of a sedge bed in this way. You just hang around a while and the vole is sure to appear.