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MAMMAL CONFERENCE
TRACKING DOWN SUFFOLK’S HAZEL DORMICE: 15 YEARS OF DETECTIVE WORK SIMONE BULLION Hazel dormice are highly arboreal, native, small mammals primarily associated with ancient woodlands and hedgerows. Their exacting habitat requirements make them extremely scarce and consequently they are rarely seen in the wild. Occasionally, hibernating dormice are discovered during woodland management work such as coppicing. However, as there have been few such reports during the last decade, dormouse surveying is dependent upon locating their distinctive field signs. They make woven nests in dense vegetation in the shrub layer, usually out of stripped bark, but occasionally using tall grasses or sedges where available. This woven ball is then encased in leaves such as hazel or bramble. In addition, they also open hazelnut shells in a very distinctive way by creating perfectly round holes with a smooth edge, contrasting with wood mice and bank voles which also make a round hole, but with a chiselled entrance into the nut. However, in the absence of dense thickets where these aerial nests can be more easily found, or fruiting hazel providing an abundance of nuts, their presence can be extremely difficult to detect. One hundred years ago, dormice could be found in most counties across England and Wales, with their distribution reaching as far as Yorkshire, Cumbria and Northumbria. It is likely that across much of this range they were already becoming scarcer and their populations fragmented, except across southern England where they are known to have been commonest. The current distribution indicates that there has been a significant contraction in range southwards, with populations being lost from all of the northern counties apart from Cumbria and also losses from the Midlands. As part of the Species Recovery initiative, a captive breeding programme (coordinated by The People’s Trust for Endangered Species (PTES)) has reintroduced populations at nineteen sites to date across the UK, including two in Suffolk. In the Suffolk Victoria County History, Rope (1885) described dormice as commonest in the west central district and also in the woods around Belstead and Bentley. Julian Roughton conducted a ‘nut search’ on behalf of Suffolk Wildlife Trust (SWT) in 1986 and confirmed dormice were still present in two of the original ‘Victorian’ sites as well as recording their presence in six new locations. The Great Nut Hunt of 1993-4 (Bright et al., 1996) also confirmed their presence at two of these southern locations. Around this time, the dormice in the SWT reserve at Bradfield Woods were rarely seen, as investigated by Martin Hicks’ PhD fieldwork on the effects of coppicing on dormice. By the time the author became involved in studying Suffolk’s dormice in 1998, they were only known at a single site in south Suffolk at Tiger Hill, Assington, so it was agreed that SWT would once again undertake a nut search using volunteers during the winter of 1998/99. This resulted in the discovery of a scattering of records in the south of the county within the parishes of Assington, Polstead and Bentley. In 2000, a captive-bred release took place into Priestley Wood in Barking and a regular monitoring programme started at this site using 200 wooden nest boxes.
Trans. Suffolk Nat. Soc. 51 (2015)