There are four species of Gliridae or dormice in Bavaria: the edible dormouse or fat dormouse (Glis glis), the forest dormouse (Dryomys nitedula), the hazel dormouse or common dormouse (Muscardinus avellanarius), and the garden dormouse (Eliomys quercinus). The forest dormouse is extremely rare, having only been shown to inhabit the Isar and Inn valleys in the Bavarian Alps. Edible dormice and hazel dormice are the most common, and prefer flat and hilly country with abundant deciduous forest. The garden dormouse is rarer. In Bavaria it mainly colonises coniferous and mixed coniferous forests.
The garden dormouse has a striking appearance, with its light-coloured tummy, reddish brown back and the dark circles around its eyes. Its mask in particular distinguishes it clearly from the silver-grey edible dormouse, whose face is completely lacking in striking colouring (Fig. 2).
Garden dormice are nocturnal omnivores, although animal sources of food dominate. They eat insects, caterpillars, millipedes, woodlice and slugs and snails, for example. Particularly in autumn, they also eat vegetable matter such as seeds and all sorts of fruit.
After hibernating for several months, they begin their rather vociferous mating season in April/May. After mating, the female builds a nest of leaves and moss, where it usually delivers four to six young after a gestation period of 21 to 23 days. The males do not play a part in taking care of the brood. After around 40 days, the young are independent. They reach sexual maturity the following year.
In Europe, the garden dormouse was originally prevalent from Portugal all the way across to the Ural mountains. However, its range has diminished in size by up to 50% over the last 30 years. Whereas now it only has a few larger contiguous areas of distribution remaining in central and eastern Europe, it still occurs across extensive areas particularly of south-western Europe, in France and Spain.
In Bavaria, the main range of the garden dormouse is in the eastern Bavarian border areas: in the Frankenwald forest, the Fichtelgebirge mountains and the Bavarian Forest. It also has smaller contiguous areas of distribution in the Spessart forest and on the edge of the Steigerwald forest. In neighbouring Thuringia, this dormouse occurs in the Thüringer Wald forest and Thüringian Schiefergebirge (slate mountains) (Fig. 3).
Unlike the edible dormouse, garden dormice are out and about more at ground level. They need the tree stumps and deadwood lying there to hide in, and berries and mosses as a source of food. As hiding places and places to spend the winter, natural boulder fields or slate heaps (Frankenwald forest) also play an important role for them.
The varied structures of the coniferous forests in the Frankenwald at elevations above 500m are also extremely important for this species. The garden dormouse has however also retreated over the last few years from areas it used to occupy at higher elevations - both in the Frankenwald forest and in Thuringia. This may have something to do with the edible dormouse, which loves warmth and tends to live in lower areas, but which is increasingly spreading.
Because of the decline of the garden dormouse in many parts of Europe, a biodiversity project has been started in the Nature Parks of the Fichtelgebirge mountains and Frankenwald forest as part of a state-funded campaign to promote species diversity in Bavaria (“Aktionsprogramm Bayerische Artenvielfalt”).