Harvest Mouse Welfare: Tiny Mammals of the Field Margins

Harvest mice are Britain smallest rodent and weave spherical nests in tall grass. Intensive agriculture has dramatically reduced their numbers by eliminating the rough field margins they depend on.

Key Facts

Harvest mice weigh just 4-6 grams and are the only British mammal with a prehensile tail
They weave spherical nests from grass blades in tall vegetation for breeding and shelter
Harvest mouse populations have declined by an estimated 70% since the 1970s
The loss of traditional hay meadows, hedge banks, and rough field margins has eliminated most of their habitat
Harvest mice struggle to survive in arable fields dominated by regularly harvested crops

Welfare Considerations

Harvest mice experience welfare harms through the loss of the complex, structurally diverse vegetation they need for shelter, food, and breeding. Combine harvesting and regular grass cutting destroy nests during breeding season, killing young. Pesticide use eliminates the insects and seeds that they rely on for nutrition. Extreme cold events cause mortality in a species too small to store significant fat reserves. Restoring field margins and reducing mowing frequency in autumn are among the most direct welfare improvements available to farmers.

What You Can Do

Support agri-environment schemes that fund rough field margin creation on farms
Delay autumn grass cutting on road verges and field edges to protect harvest mouse nests
Donate to harvest mouse conservation projects run by county wildlife trusts
Plant tall native grasses and wildflowers in garden areas to create harvest mouse habitat