Humans have never deliberately persecuted harvest mice since their small appetites do little to affect crop yields. They even do the farmer a small favour by eating harmful pests such as aphids. However, they seem to be less numerous in cornfields than they used to be. This is most likely due to changing farming methods such as combine harvesting, reduced stubble length, stubble burning (though this is being phased out) and crop spraying.
Harvest mice must have shelter to retreat to once the crop has been harvested so hedgerows are an important habitat for them, providing food as well as shelter. When hayricks were more common, many mice over-wintered in these.
Although harvest mice may have decreased in some agricultural areas, there is evidence that they are widespread, even increasing, in other habitats, especially the undisturbed areas along motorway embankments.
The harvest mouse is not protected by law and it is possible it may become an endangered species in the future. It is important to conserve favoured habitats, particularly hedgerows.