It was a lovely sunny Autumnal afternoon with the threat of rain as Catherine, Veronica and myself set out to see if we could find signs that field voles resided at Gibside. We had carried out some mini mammal trapping in September but field voles are obviously a bit more savvy and seem to be able to avoid the traps. So the way that we survey for them is to look for the signs that they leave behind.
Similarly to when we set the traps for our first survey, you choose a 100m long section of the mammals favorite habitat. In this case field voles love lots of long, uncut grass that you might find on road-side verges, woodland rides, field edges or along fence-lines or walls. Then at every 10m point of your 100m line you search for 10 minutes within a 1m squared area for signs of the voles.
As you begin to part the thick grass the first sign that you may see are the little runs that are created as the voles make their way amongst the grass looking for food.
Then as you look closer you'll see little piles of grass where they have chewed the lush, green shoots of grass and left the leafy tops. If you look closely at the ends of these bits of grass you can see the jagged edges where they have been nibbled.
Sometimes you just find one or two bits of grass and other times you might find a whole pile of them.
The third sign that you are looking for are their latrines. These are prominent areas where they deposit their faeces. Not the nicest thing to be looking for but with all wildlife it is a definite sign that they are around even if you don't see them.
The forth sign that you are looking for are their nests, these are made of woven grass and generally can be found in dense vegetation at ground level. We didn't find any nests on this occasion but as Veronica explained they only use nests during the breeding season in the summer then abandon them, so by the time it comes to the survey the nests could be flattenned and misshapen and no longer look like a nest so they are very hard to spot.
For my first attempt at searching for signs of field vole I was very pleased with the result. We searched along two 100m long sites at Gibside and found signs of field vole at both. This data will be added to The Mammal Societies national database as well as contributing to Gibsides records. I hope we are as successful next year.
Eventhough we didn't spot one, this is what a field vole looks like.