A full version of this article appears in the magazine.

Until 1992 it was assumed that the Hazel or Common Dormouse Muscardinus avellanarius was not present in north Wales. Since 2007 the amount of work on dormice in north Wales has increased significantly. Here are some of the activities and findings so far…

 

Partnership working

Amongst the benefits of working with a charismatic and endangered species like the dormouse is the way it brings disparate organisations together, increasing the expertise, volunteers and funding available for research and conservation. Much dormouse research in north-west England and north Wales since 2005 has been undertaken by the North West Dormouse Partnership, focussing mainly on dormice at Coed Fron Wyllt (Bontuchel, near Ruthin) and the reintroduced population in the Wych Valley on the Cheshire/Wrexham border.

 

In 2007 a new North Wales Wildlife Trust (NWWT) initiative extended work on the dormice into the area around Coed Fron Wyllt (which has one of the highest dormouse densities in the UK) and installed dormouse nest boxes at sites in the Conwy Valley. As Dormouse Officer at NWWT, I (Rhian) have been monitoring dormouse sites across north Wales for the last few years.

 

Visit Coed Fron Wyllt or the Wych valley during one of the four survey sessions each year, and you might wonder what was going on. At each session a group of around 20 keen volunteers and a ‘vet team’ spread out through the woodland, braving waist-height bramble, and enduring biting insects! Painful as it may be, the dormice are worth it.

 

Which dormouse?

Each dormouse we find is micro-chipped. This means we can identify individuals if we find them again, and enables us to understand their behaviour better. For example we can calculate how long our dormice are living, how far they travel, whether pairs stay together from year to year, and if they show loyalty to particular nest boxes.

 

Between May 2005 and May 2010 we have marked a total of 811 dormice at the two sites. Of those animals 32% have been recaptured at least once, and 15% have been found more often than that.

 

Our most well known dormouse is a female who was first captured and micro-chipped at Coed Fron Wyllt in July 2006 as a juvenile. Since then we have seen her nine times, and know that she bred in 2009 and may also have had young in 2007.

 

Our longest lived animals are also females from Coed Fron Wyllt, who were both marked in June 2005 and last seen in 2009. As they were mature adults when first captured in 2005, we can confidently assume that they were born in 2004 or earlier, indicating that they are at least five years old. Other studies have shown wild dormice have varying life spans in different regions. In Lithuania six-year olds have been recorded occasionally; in Britain few animals have been shown to have survived for more than five years, and three to four years is more common in central Europe.

 

Our study is just reaching the 6th year and we are really hoping to see some of our ‘old friends’ again! Other studies have found that males tend to live longer than females, so it could be that our dormice are different in this aspect too. Our studies have also shown that juvenile dormice move greater distances in their first year than adults do, supporting other evidence for a dispersal phase in the first year.

 

Dormouse Family Scandal!

DNA fingerprinting research has shown that most litters of baby dormice have more than one father; it was previously assumed that litter siblings all had the same father. Clearly female dormice are quite promiscuous! DNA fingerprinting also helped explain an interesting instance where two females were found occupying the same nest box, with one litter of babies – it revealed that the females were sisters.

 

DNA research also investigates dispersal of dormice in north Wales, especially those surrounding Coed Fron Wyllt. It appears that they can spread quite far in large patches of habitat, such as Coed Fron Wyllt, but rarely move into neighbouring areas that are separated by farmland. Further monitoring will reveal the impact of hedgerow maintenance in facilitating dispersal.

 

Habitats

A previous article (Natur Cymru No 1) told how some dormice are found in conifer woodlands. This is confirmed by evidence in north Wales too, challenging traditional wisdom which states dormice need coppiced hazel woodlands. The fact is that woodlands with hazel understoreys are the easiest places to find evidence of dormice, but the animals are now being found in more and more habitats in the UK.

 

Extensive surveys in Dorset have found dormice in gorse and coastal blackthorn scrub, oak woodlands, hedgerows and conifer plantations. Preliminary vegetation studies at Coed Fron Wyllt indicate that plant species diversity is important for dormice, providing plenty of options for food, nest sites and nest materials. Areas with a well-developed understorey and mixed tree species seem to be favoured.

 

Canopy boxes

After speaking to Jack Grasse, and visiting his dormouse sites near Corris to see his high canopy nest boxes, it was decided to try something similar. Canopy boxes are made out of drain pipe and have a door mechanism which can be closed from the ground when the box is located about 10m up a tree.

 

At Coed Fron Wyllt 20 boxes were erected in close proximity to the low-level nest boxes already in place. The boxes were used by the time they were first checked (November 2008); when checked last October (2009) eight boxes being occupied by a total of 12 dormice, of which only two had previously been micro-chipped.

 

We have now found dormice using these high boxes in two of the three sites where they have been installed.

 

Rhian Hughes is Dormouse Project Officer, North Wales Wildlife Trust; Sarah Bird is Biodiversity Officer, Chester Zoo; Sue Tatman is Dormouse Project Officer, Cheshire Wildlife Trust; and Dr Phill Watts is a Senior Lecturer in the School of Biological Sciences, University of Liverpool.

 

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