Helping Hands for Harvest Mice

Harvest mice (Micromys minutus) are the smallest rodents in Britain weighing 6g at adulthood (the same as a 50p piece). Listed on the IUCN Red List as “Near Threatened” they are patchily distributed but often in high numbers. However, they are prone to population crashes resulting from habitat loss and increased summer rainfall due to the effects of climate change. Their prehensile tail enables them to climb in the stalk zone of ruderal vegetation and they are known to be highly adaptable. However, these enigmatic creatures are rarely seen and few records of them exist in Sussex.

During the development of the EPIC project we ran two introductory events to gauge peoples interest in their local greenspace and getting involved in monitoring it into the future. During these events we undertook small mammal trapping as it is an easy and safe way to enable people to connect with nature. 

We were delighted to capture a harvest mouse at the top of the site on the first event and subsequent nest searches of the wider landscape proved they were present in the ditch network and Cokeham Reedbed Local Wildlife Site which are all contained within the Sompting Brooks.

To our professional small mammal researchers this was too good to be true and it clearly inspired the local community volunteers to know more. Out of this the Helping Hands for Harvest Mice Citizen Science project was created. 

Since late 2018 we have continued to monitoring the harvest mouse population on site. Assisted by our team of volunteers from the local community we have undertaken nest searches and live trapping to look at distribution across the site, looked at the impact of vegetation removal (displacement) on survival and movement of harvest mice and other small mammals, assessing its effectiveness as a technique for ecological mitigation. We have also taken genetic samples (from hair) to look at how connected the populations across the site are, the levels of related and diversity in discrete populations. 

All of this information is being used to inform us on future site management as well as look at wider landscape connectivity in this urban fringe site. 

Whilst the project is ongoing, we have undertaken two trapping sessions lasting a total of 13 days. We have captured 387 individuals from eight different small mammal species including 14 harvest mice. Our displacement experiment worked with around 40% of individuals re-captured following the works to clear vegetation (we will be publishing these results over the next 12 months). We have also found over 100 nests across the site and the genetic work in the laboratory has begun and we are excited to see what these results show about our local population. 

We will continue to post updates to the project here and you can see our results posters and updates by clicking on the following links or check out our harvest mouse fact sheet.

Spring 2020 – Cancelled 

Autumn 2019 – Harvest Mouse Newsletter

Spring 2019 – Results Poster and Nest Search Results