This central blur is two voles having a furious fight!
Dark and fluffy baby vole.
The dark fur of a juvenile.
When the population starts to peak and numbers are robust, individual voles do become quite bold. With each other, adults are intolerant and a lot of chasing and fighting goes on. Even young voles are sent packing. However, within a week or so, the new generation will disperse to find their own territories, and this boldness disappears and sightings drop off. In the past I've panicked and thought a predator had been at work, but now I see it's a perfectly natural rhythm of the colony that after the start of July, I see fewer voles that I did the month before.