Tales of Dorset dormice

Although, the PTES’ State of Britain’s Dormice 2019 report has revealed that Britain’s population of hazel dormice has declined by 51% since 2000, decreasing on average by 3.8% per year, Dorset seems to be bucking the trend. To put you in the picture, the PTES’ National Dormouse Monitoring Programme (NDMP) claims to be the longest-running small terrestrial mammal monitoring programme in the world. It was established in 1990, so has 30 years of data to back it up.

To find out specifically about Dorset, I spoke to Ian White, the PTES’ dormouse and training officer (isn’t that a lovely job title?).

On the surface, the news seemed positive in that Dorset dormice populations don’t appear to be declining, but here’s the reality: it is hard to tell. Apparently, dormice are such little critters (about 60mm in length, plus a tail) they are difficult to see, let alone count. It was a bit of a blow to learn these facts, and slightly took the edge off my belief that Dorset was the success story of the year.

Anyway, Ian elaborated a further, “Research in the county is limited and there are no population estimates for any region or indeed the whole country.”
Okay, so how does PTES find out how the dormouse is faring? This was a need-to-know question.

Ian explained, “We sample a proportion of the population and believe the trend of the sampled population mirrors that of the wider population. From our National Dormouse Monitoring Programme (which has been running for 30 years), we know that dormouse populations have declined by 51% since 2000. And while we haven’t undertaken a specific analysis of Dorset’s data, it does appear that dormice in the southern counties, including Dorset, are faring better than the national average.”

On the basis of the dormouse officer’s knowledge, I have to assume that Dorset dormice are doing well, so I asked if there were any known hot spots in the county and Ian said, “We believe dormouse populations are widespread throughout Dorset. Therefore there aren’t any known hotspots per se, which is seen in the neighbouring county of Hampshire too.”

The fact that the PTES believes dormouse populations are widespread throughout Dorset, and Hampshire by the sounds of it, is quite exciting.

What I wanted to know next was the factors that are driving the decline of dormice nationally and Ian said, in general, there are three: lack of traditional woodland management practices, loss of habitat, and climate change.

There is little anyone can do about climate change, unless the mind-set of world itself changes, but it does seem dormice are sensitive to this element. Variable temperatures over winter can make their hibernation unsuccessful, sometimes resulting in death. “In addition, wet springs and summers can affect their ability to produce litters, impacting future generations,” said Ian.

If you have a bramble hedge, which is prime dormouse habitat and a food source, Ian suggests you can “create a structured hedge where bramble can grow through it, and simply cut that back when necessary. This way, the connecting link is always present and maintained.”

Another way you can help is by volunteering for a local conservation organisation. Ian said, “Correct woodland and scrub management is key to the long-term survival of dormice in the UK. To help, people can volunteer for their local conservation organisation helping with reserve and woodland management. For those who are unable to help physically, supporting charities like People’s Trust for Endangered Species so their conservation work with one of the UK’s most enigmatic native mammals can continue, is always hugely appreciated.”

Although dormice have been reintroduced in other counties, where populations had been lost, Ian said, “Dorset remains a stronghold for hazel dormice,” so there “has not been a reintroduction in Dorset, nor is one likely to be considered in the future – which is great news for dormice locally.”

The prospect of seeing a dormouse seems pretty remote. Ian told me that due to their secretive, arboreal and nocturnal nature, the chances of seeing a dormouse are highly unlikely. However, on the plus side, he did mention that there have been reports of dormice being spotted on bird feeders in rural gardens this summer.

If you think you’ve seen a dormouse, please take and send a photo to PTES, so that they can verify your sighting and record it on their database: enquiries@ptes.org

• Usually adult dormice weigh about 20g, which is the weight of 2 x £1 coins. In autumn, they can start to put on weight ahead of hibernation – the heaviest dormouse recorded was a whopping 44g.
• The average litter size is 4. When dormice are born, they are pink, hairless and weigh about 1g – that’s the weight of a raisin.
• Dormice are usually weaned and can become independent when they are about 10g.
• Young dormice can increase their weight by a whopping 1g a day in autumn.

Last year (2020) Dorset Council announced that two separate litters of six juvenile dormice had been found in two areas of new growth coppice at Thorncombe Wood near Dorchester. They were discovered by licenced surveyors in a managed patch of hazel woodland. The careful management of the woodland and hard work put in by the rangers and volunteers is proving beneficial to Dorset’s resident dormouse population.

PTES, is a UK conservation charity created in 1977, committed to ensuring a future for endangered species throughout the world.

I hoped you like learning about dormice in Dorset. If you have seen one, do let me know.