I was sad to wake up to some disheartening news about the hazel dormouse (Muscardinus avellanarius) yesterday. According to a new report by the People’s Trust for Endangered Species, the native population of this mouse species has dropped a third in sixteen years.
The hazel dormouse is now only found in parts of southern England and the Welsh borders and is currently “vulnerable to extinction in Britain”. The reasons for their decline include agricultural practices, loss of hedgerow habitat, alterations to woodland management methods and the consequent fragmentation of this woodland.
To thrive, dormice need areas of woodland connected by hedgerows; these wildlife corridors enable them to spread. They also build their ball-shaped nests in these hedgerows and use the woodland cover to hibernate from October to May. Hazel dormice did particularly well when the trees were coppiced. This management technique involved cutting a tree to its base and leaving it; when the tree regrew it branched into two separate trunks, providing more fruit for the mice to feed on. However, in many cases the areas of woodland changed too quickly for the mice to adapt. Two thirds of native hedgerow were lost, leaving the mice that survived isolated from food sources and other mice to breed with.
For the past 25 years, the People’s Trust for Endangered Species has been running the National Dormouse Monitoring Programme (NDMP). Several hundred monitors have the important responsibility of carrying out surveys using dormouse boxes and recording their sightings. Anyone interested in becoming a monitor would need to obtain a dormouse licence from Natural England or Natural Resources Wales. However, the Trust also accepts one-off sightings via the National Dormouse Database, so anyone can help the valuable work the Trust is doing. As dormice are protected by government and regarded as a priority for conservation action, the monitoring of a used nest box requires a licence.
The Trust have also carried out 24 reintroductions, meaning the dormice are now present in six of the counties in which they had previously been extinct. Although the reintroduced populations have died at five of the chosen sites, at another five the individuals successfully spread through their new woodland habitat. At another seven of the sites, the dormice ventured further into the woodland and into the surrounding farmland, making their reintroduction a huge success. Following a reintroduction in June 2015, evidence of breeding has been gathered, including footage of a young dormouse getting to grips with climbing trees. The short clip by Lorna Griffiths is well worth the watch.
Anyone wanting to know more about the dormouse reintroductions can follow the link to the Natural England website. Although I was sad to hear that hazel dormice are struggling, the news prompted me to research and write this post, and I’ve thoroughly enjoyed learning more about these enchanting animals.