I’m so cold! My feet are frozen! said Huma. It was indeed a chilly bright winter’s morning. We were grateful when the sun came up and warmed the glade where Vole Patrol had set up its measuring station, with tarpaulin, big sacks for opening traps, small bags for weighing and measuring, all the traps in order, scissors to code the animals’ backs, rulers, scales, fresh hay and three types of bait.

Unlike the meagre daytime catch of yesterday afternoon, 20 of the traps contained mice.

I had a go at measuring and coding; then Huma put a mouse back in the big sack, as if just out of an opened trap, and under her watchful eye I caught it gently by its scruff, transferred it to a small bag, and weighed it. I’m a mammal wrangler! The main difficulty, apart from their remarkable ability to escape, is that they hunch up, making straight-line measurements rather tricky.

Only one other trap had been triggered, so the false alarm rate was well down now: resetting the sensitivity of all the traps had been more than justified.

We were soon very busy: bringing in the full traps; opening them, catching the mice, coding their back fur, measuring, weighing, carrying them back to where they came from and releasing them.

Tony the ecologist, who helped with the trapping today, said he’d expected Wood Mice rather than voles. Voles cannot easily make their way along railway embankments as they’re predated by Foxes and Badgers, which freely use railway  “corridors”. Small isolated populations can easily die out, which is probably what happened here.