The Hazel/Common Dormouse (Muscardinus avellanarius) or Pathew in Welsh is Britain’s only native species of dormouse. Once widespread throughout most of Britain it is now generally restricted to the southern parts of England and Wales due to changes in woodland management, farming practices, loss of hedgerows and fragmentation of woodland. Within Wales the distribution of dormouse is patchy, with Carmarthenshire being one of the counties with a reasonable coverage of records. If you draw an imaginary line along the river Twyi and take the south-eastern corner of the county, this is the dormouse stronghold area. Elsewhere dormice are more patchily distributed. The nearest records outside of the county are in north Pembrokeshire, Gower, Brecon and Bridgend.

Traditionally suitable dormouse habitat was taken to be deciduous woodland with abundant secondary growth, coppice and species-rich hedgerows. Our dormice are definitely not traditionalists as, although they are found in woodland, they are also found in hedgerows which can be quite species poor, scrub on old coal tips, very small patches of woodland and there is even a record of dormice using a tennis ball aimed at recording harvest mice in a reed bed. One of the things that Carmarthenshire’s dormice definitely love is bramble – a nice thick swathe of bramble next to a hedge seems to be dormouse heaven.

Dormouse populations are monitoring by using dormouse boxes which are very similar to bird nest boxes. The most long-standing site within Carmarthenshire that has been monitored for dormice is the Wildlife Trust site of Rhos Cefn Bryn near Llannon. Using dormouse boxes the small copse and hedgerows present have been monitored for about 15 years on and off. The dormice were originally confirmed to be present within the copse and one hedgerow, since when the central hedgerow within the reserve has been thickened with additional planting and fenced to prevent grazing. In the past three years it has been confirmed that dormice are now using central hedgerow and have been proven to be using most the hedgerows on the reserve. Each year the records from Rhos Cefn Bryn are added to the National Dormouse Monitoring Programme run by the People’s Trust for Endangered Species (PTES) which collects data where dormice are monitored all over the UK.

The boxes, about 45 in total, are checked monthly through the summer and the largest number of dormice ever recorded in one visit was 15 in September 2007! This year and last has seen much lower numbers with no signs of breeding. Why did we have a bumper crop of dormice in 2007? It could be the weather, dormice like it dry and warm in the summer so sometimes I think it’s a miracle we have them at all! With the past three summers being wet even for us, is it the weather that has depressed their numbers and thus reduced the use of boxes? But that wouldn’t account for the bumper crop being in 2007, which was one of the wet years. We did put a load of new boxes up in the copse early in 2007. So do we have a population of discerning dormice, only new boxes will do? Those old ones with the slugs, earwigs and mould can be left for the birds, pygmy shrews and wood mice? We hope next year to try to find out. We are planning to trial some new boxes made from drain pipes which should be drier. We’ll put these next to the wooden ones and see if they will be used.