Episode 12: Hazel dormouse

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With the new ” Lend an ear to nature” campaign, the Mouvement Ecologique wants to draw attention to these often-threatened species and their habitats – and combine it with a guessing quiz on the noise of the animal in question.

A total of two short videos on a species of animal from our localities and landscapes will be published each month from the end of April until October.

Guess with us – which animal is making that sound? and win a Naturata voucher worth €50 per spot!

 

 

 

 

 

 

(c) Adobe

Did you recognise the hazel dormouse in the clip?

Yes, admittedly – this was probably the trickiest quiz in our campaign. Very few people have ever consciously heard the snoring of a hazel dormouse. And yet we wanted to use this cute recording to draw attention to the nature around us. Because even in winter – this seemingly quiet season – life has not disappeared, it is just taking a break. Many animals hibernate, and for this they need safe, sheltered places.

This includes the hazel dormouse, which, incidentally, is not a mouse at all, but belongs to the gliridae family – also known as dormice. From October onwards, it curls up for several months of hibernation. With its large, dark beady eyes and bushy tail, it is easy to recognise – if you ever get to see this secretive goblin of our hedgerows.

 

Way of life

The dormouse is relatively small, measuring 5-8 cm. Its distinctive feature is its bushy tail, which is similar in length to its body. It is nocturnal and extremely adept at climbing. During the day, it rests in spherical nests which are built knee-high in dense bushes, hedges and blackberry bushes.

During the warm months, it roams through the branches at night, feeding on fruits, nuts, berries, flower parts, seeds and also insects or small invertebrates. It rarely leaves the structure of the hedge, which is why it depends on well-connected bushes – this way, it avoids dangers lurking on the ground.

As it is a very secretive animal, its presence can often only be detected indirectly: by finding its spherical nests or particularly artistically gnawed hazelnuts. In contrast to the holes gnawed by mice, the bite marks of the hazel dormouse run parallel to the opening (see picture).

When autumn arrives, it builds up fat reserves and prepares for hibernation. From October until spring (usually until April), it remains asleep in its protected nests.

 

(c) Zoë Helene Kindermann, CC BY-SA 4.0

 

Dangers and threats

The hazel dormouse suffers greatly from the decline and fragmentation of its habitats. Hedges and shrubbery are being destroyed, forest paths mowed and brambles removed – this takes away important connecting corridors (habitat corridors) that it uses to climb safely from bush to bush. In such heavily fragmented landscapes, its range of movement is very limited and it is often unable to reach new habitats.

Climatic factors and changes in temperature and precipitation also have an impact: for stable hibernation, they need constant, low temperatures in the range of about 1–4 °C. Significant fluctuations in temperature or precipitation can disrupt hibernation. This leads to increased losses, as these waking phases in winter consume a lot of energy that they cannot compensate for at that time of year, as there are no more berries or nuts available.

In addition, the decline in food diversity – for example, when fewer berries, nuts or insects are available due to the planting of non-native trees and shrubs – harms their ability to survive.

Another risk is the high density of predators such as martens or free-roaming domestic cats, especially in areas where there are already fewer hedges and they are more exposed to these predators.

 

Distribution in Luxembourg

With the ‘Aktioun Schléifer’ campaign, the Mouvement Ecologique worked with citizens from 2021 to 2023 to document the occurrence of hazel dormice, garden dormice and fat dormice throughout the country. The numerous reports – with the exception of the Ösling plateau – have significantly improved the data situation, even if such a citizen science campaign cannot replace a systematic scientific survey.

As the hazel dormouse is protected under Annex IV of the EU Habitats Directive, Luxembourg must report on its conservation status to the European Commission every six years. To this end, the Ministry of the Environment has been conducting a nationwide, scientifically based study of this species in collaboration with the Luxembourg Institute of Science and Technology (LIST) since 2010. These studies also confirm that the hazel dormouse is present in large parts of the country.

Its main areas of distribution are hedgerow-rich landscapes and species-rich forest edges with herbaceous vegetation and blackberry hedges. In recent years, there has also been increasing evidence of their presence in scrubby clear-cuts and natural regeneration areas in forests. The presence of blackberry hedges seems to be a constant feature of their habitats, which has earned them the nickname ‘blackberry dormouse’.

However, it is becoming increasingly apparent that hazel dormouse populations are becoming more and more isolated because, unfortunately, excessive logging means that the canopy closure along roads and paths through forests is often no longer guaranteed. It is also worrying that their habitats – hedges, orchards and forest edges – are increasingly being lost to development and intensive agriculture and forestry.

All information about the campaign and additional documentation can be found here: https://naturelo.meco.lu/projekt/aktioun-schleifer/

 

How can you help the hazel dormouse?

Plant native hedges

  • Preserve and plant native hedges and shrubs as habitats and corridors for the hazel dormouse. Choose native shrubs, e.g. ‘Heck vun hei’, and make sure you have as wide a mix of different species as possible to diversify the food supply of berries and hazelnuts. Especially in autumn, the high-fat hazelnuts are essential for building up winter reserves (hence their name!).

Promote diverse, structured forest edges

  • If you own a forest, manage it in a natural way: maintain a mixture of native trees and shrubs and preserve old and dead wood. A high proportion of young trees, shrubs and deciduous trees provides the dormouse with the vertical structure it needs.
  • Also avoid dense coniferous stands above the hazel dormice’s edge habitats: studies show that hazel dormice use nests less when Douglas firs or spruces provide too much cover above them. Maintain herbaceous edges and forest edges with blackberry hedges.

Support monitoring and conservation projects

  • Go hunting for hazelnuts and document your findings using the inaturalist app. More information here: https://naturelo.meco.lu/nossjuegt/
  • Encourage your local authority to take the hazel dormouse into account when planning green spaces and to implement protective measures such as planting hedges.

 

Further information on the hazel dormouse can be found here: