Harvest mice surveys at Marwell

Did you know the harvest mouse (Micromys minutus) is the smallest mouse in the UK? These tiny creatures live in grassy areas like meadows and hedgerows across the country.

They are an important part of our ecosystem because they eat seeds, which helps plants spread and grow. They also make a tasty snack for animals like owls, foxes, and weasels – this makes them a key part of the food chain!

Harvest mice are tiny and weigh the same as a 2 pence piece, which makes them very hard to spot. So, instead of looking for the mice themselves, we look for their nests. This helps us find out how many there are, how they’re doing, and what we need to do to protect them.

Harvest mouse nests

Female harvest mice make small, round nests that are woven out of grass. They build these nests up in tall plants to keep their babies safe from predators. In the winter, once the babies have left home, these nests are abandoned. This is the best time to go out and look for them, because we don’t disturb the animals.

Our first harvest mouse survey

At Marwell, some of our team and students carried out a harvest mouse nest survey in our ancient woodlands and chalk grasslands. We haven’t done this before, so we were thrilled to find seven nests! This means harvest mice are living happily on our land, and that the habitat we have created is suitable for them.

Each female can build more than one nest, so finding seven nests doesn’t mean there are seven mice. We found these nests in three different areas, so we think there were at least three breeding females.

The next steps

In the coming years, we will repeat the surveys to see whether the populations are changing, and whether we can find any more areas that they might be living in. It’s fantastic to know these tiny animals are calling Marwell home, showing just how special and healthy our habitats are!