Did the water vole colony survive the destruction of their habitat

It appears that the water voles have survived on the south bank directly opposite the zone that was destroyed.

These photos were taken on a very cold 26th December 2009. The voles would have not have been out and about at this time of year (very sensible) so there were no signs or footprints to be seen. And the water level in the Beck was high so it was not possible to get up to the holes. These were taken from the bank.

The question is, did we miss these holes or have the voles moved?

The bottom left shows both banks a few days after the northern bank habitat was destroyed. The coverage of spring foliage can be seen (and the same area in winter). So the signs might have been missed because of the coverage.

But, if you look at the photos, it appears that the bucket used when the site was destroyed has also scraped the southern bank. In the 9 months since this criminal action, the beck has softened the edges. And it is through the new mud that the holes appear.

So did the little voles have to dig their way out from their holes or did they move across the beck to the softer, southern bank?