Harvest Mouse

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What is a Harvest mouse?

The harvest mouse is Britain’s smallest rodent with a body length of 5-8cm and weight of less than a 2p coin. It has adapted to human agriculture by living in the margins of cereal crops although can also be found in other similarly structured habitats such as reedbeds. It’s equally at home above water or dry ground, helped considerably by a semi-prehensile tail that’s almost the same length as its body. It’s largely nocturnal and its presence is usually indicated by its tennis ball-sized nest woven out of grasses and suspended between plant stems usually 30-60cm above the ground and often higher when above water. It’s thought they can build an entire nest in a single night.

Why is Harvest mouse important to the Surrey Hills?

Protected from deliberate cruelty under the Wild Mammals Protection Act. Priority Species under the UK Post-2010 Biodiversity Framework.

What habitat does the Harvest mouse like?


Arable is currently is one of the most intensively managed land uses and covers a multitude of crops from the most basic commodity products such as wheat, oilseed rape, sugar beet and potatoes to more specialist crops such as linseed and asparagus. Some crops are annual while others, particularly salad crops, can yield two or three crops each year on the same piece of land.

How to support the Harvest mouse

Good management and habitat creation opportunities for the harvest mouse include:
  • Tussocky grass margins left uncut for 3-5 years allowing some grasses to grow enough to support nests.
  • Establishing wild bird mixes that include millet as it’s both an ideal food source and nesting habitat.
  • Providing corridors of tussocky grassland to encourage movement and prevent populations becoming isolated.
  • Leaving open glades in new tree planting schemes that allow sunlight in and encourages grass growth.
  • Allowing vegetation to grow by ponds, ditches, streams and other wetland habitats.
  • Not allowing the base of hedges to be grazed out by livestock.


Creating and managing areas for the Harvest mouse will help deliver the following benefits to communities:
  • Clean water
  • Clean air
  • Protection from and mitigation of environmental hazards
  • Mitigation of and adaptation to climate change
  • Thriving plants and wildlife
  • Beauty, heritage and engagement

Current conservation projects

Over the winter months, the Society will be getting involved with the National Harvest Mouse Nest Survey, coordinated by The Mammal Society. This survey involves looking for Harvest Mice nests abandoned from the summer to identify Harvest Mice presence. We are hoping to run a training session for this survey in the New Year.

These illustrations are by an artist taking part in a programme delivered by Watts Gallery Trust and funded by the Michael Varah Memorial Fund. This series of 30 Surrey Hills Indicator Species were commissioned by Surrey Hills Society and funded by Surrey Hills Trust Fund as part of the Making Space for Nature Exhibition.