The harvest mouse (Micromys minutus) is often overlooked by humans; maybe they just don’t see this ingenious little creature scurrying around in the long grass and fields. The harvest mouse is in fact Britain’s smallest rodent. It inhabits the wetlands and long grass and is highly active throughout the day and the night, however they are most active at dawn and dusk. The harvest mouse is highly adaptable, intelligent and opportunistic allowing it to live in the marginal habitats between two ecosystems. This is coupled with the fact that it does not hibernate over winter like a few of the other British rodents do.

The harvest mouse is easily described as having a blunt nose, small eyes and unlike most British rodents has small ears as well as a prehensile tail allowing for better balance and movement. The mouse is on average sized between 5 to 7cm and weighing roughly 4 to 6g they are very small and very light, aiding in hiding from predators, however this does come at the costs of a very short lifespan of roughly 18months and having a high calorific requirement. The harvest mouse as stated before is highly opportunistic having a very wide range of food sources including a mixture of seeds, berries and insects as well as some fungi, roots and moss has been observed. The harvest mouse occasionally lives up to its name in which it takes some cereals from cultivated fields.

If searching for harvest mice the best place to see these nimble little fellows is areas of tall grass, edges of cereal fields, road side verges and hedges, reed beds and some salt marshes. This is primarily because of abundance of food and the mice’s ability to climb. This climbing allows the harvest mice reach and feed in the “stalk zone” of the habitats it lives in. Nests are also built in this stalk zone; the nests consist of woven grass raised from ground found in densely vegetated grasses, hedgerows, brambles and reeds. The short life span of the harvest mouse results in there being usually two or three litters in the year within the warmer months, with most being born in August. There is usually six offspring in a litter with fast developing new-borns often exploring out of the nest by the 11th day and are fully abandoned after the 16th day within the original nest. Cold and wet weather is often a cause for mortality within the new-borns and younger harvest mice explaining why most births are during the warmer months.

The harvest mice has a large range of predators ranging from other mammals like weasels, foxes and stoats to the avian predators including owls, hawks and crows. The harvest mouse has adapted its acute hearing to survive against this predation, with a range of roughly 7 metres. When they hear a potential predator the mouse either freezes in place or drop down into a more sheltered place to hide in cover.

Harvest mice are a native species in to the UK that has seen a slight decline in numbers in recent years resulting in conservation efforts being increased so as to maintain some habitats and change agricultural methods that cause untimely deaths, these methods are thought to be a large contributor to the decline in numbers. Next time you are walking past a hedge or a field you never know how any beady little eyes might be looking out at you.