Danny Green / Hazel Dormouse (Muscardinus avellanarius) hibernating amongst leaves and acorns. Captive. Leicestershire, UK, October.

David Kjaer / Common Dormouse (Muscardinus avellanarius) sleeping on leaves. Bentley Wood, Wiltshire, May.

Ann & Steve Toon / Common dormouse (Muscardinus avellanarius)torpid, in captive breeding programme, UK

Kim Taylor / Common dormouse (Muscardinus avellanarius) hibernating in nest. Captive, UK

Colin Varndell / Dormouse (Muscardinus avellanarius) juvenile, Dorset, UK July.

Colin Varndell / Dormouse (Muscardinus avellanarius) feeding, Dorset, UK July.

Colin Varndell / Dormouse (Muscardinus avellanarius) climbing on wild cherry branch. Dorset, UK July.

Kerstin Hinze / Melanistic Common dormouse (Muscardinus avellanarius) resting on a branch, September. Captive

Colin Varndell / Dormouse (Muscardinus avellanarius) climbing in wild cherry tree. Dorset, UK July.

Kerstin Hinze / Hazel dormouse (Muscardinus avellanarius), caught in a wooden box by scientists, Voeren, Wallonia, Belgium. September.

Kerstin Hinze / Hazel dormouse (Muscardinus avellanarius), climbing a walnut tree, Wallonia, Belgium. September.

Kerstin Hinze / Hazel dormouse (Muscardinus avellanarius), climbing a walnut tree, Wallonia, Belgium. September.

Kerstin Hinze / Hazel dormouse (Muscardinus avellanarius), climbing a walnut tree, Wallonia, Belgium. September.

Kerstin Hinze / Hazel dormouse (Muscardinus avellanarius), climbing a walnut tree, Wallonia, Belgium. September.

Kerstin Hinze / Two Hazel dormice ( Muscardinus avellanarius), in nest, Hesse, Germany, October.

Colin Varndell / Dormouse (Muscardinus avellarius) pregnant female, Dorset, UK July.

David Kjaer / Common dormouse (Muscardinus avellanarius) in nest box, Wiltshire, England, UK, May.

Kim Taylor / Hazel Dormouse (Muscardinus avellanarius) in Wychelm tree in early spring. Italy, April.

Kerstin Hinze / Hazel dormice (Muscardinus avellanarius), together in one nest, Harz, Saxony-Anhalt, Germany, June.

Kerstin Hinze / Hazel dormouse (Muscardinus avellanarius), adult male, climbing on flowering Honeysuckle, Germany, June.

Ann & Steve Toon / Hazel dormouse (Muscardinus avellanarius), in researcher's hand, Nottinghamshire, UK, June

Ann & Steve Toon / Hazel dormouse (Muscardinus avellanarius) nestboxes, used in reintroduction project, Nottinghamshire, UK, June .

Ann & Steve Toon / Hazel dormouse (Muscardinus avellanarius), in researcher's hand, Nottinghamshire, UK, June

Kerstin Hinze / Common dormouse (Muscardinus avellanarius), adult on bramble branch with blackberries. captive.

Kerstin Hinze / Hazel dormouse (Muscardinus avellanarius) nest box filled with hazel nuts, Harz, Saxony-Anhalt, Germany, September.

Colin Varndell / Dormouse (Muscadinus avellarius) at night, Dorset, UK, July.

Colin Varndell / Dormouse (Muscardinus avellanarius) on cherry branch at dusk, Dorset, UK, July.

Colin Varndell / Dormouse (Muscardinus avellanarius) feeding on apple, Dorset, UK, July.

Colin Varndell / Dormouse (Muscardinus avellanarius) adult female on branch, Dorset, UK, July.

Colin Varndell / Dormouse (Muscardinus avellanarius) feeding in wild cherry tree, Dorset, UK, July.

Nick Upton / Hazel dormouse (Muscardinus avellanarius) foraging in a feeding tube supplied with fresh fruit and seeds within a 'soft release' cage. Nottinghamshire, UK, June.

Nick Upton / Hazel dormouse (Muscardinus avellanarius) exploring 'soft release' cage at dusk close to a feeding tube supplied with fresh fruit and seeds, Nottinghamshire, UK, June.

Nick Upton / Hazel dormouse (Muscardinus avellanarius) exploring among Hazel branches within a 'soft release' cage, Nottinghamshire, UK, June.

Nick Upton / Lorna Griffiths of Nottinghamshire Wildlife Trust watching a Hazel dormouse (Muscardinus avellanarius) exploring a 'soft release' cage. Nottinghamshire, UK, June. Model released.

Nick Upton / Hazel dormouse (Muscardinus avellanarius) dropping collected to be analysed for parasites before release to a Nottinghamshire wood, Dormouse rearing facility, Paignton zoo, Devon, UK, June 2014. Model...

Nick Upton / Hazel dormouse (Muscardinus avellanarius) transponder chip number read and checked ahead of release to a Nottinghamshire wood, Dormouse rearing, Paignton zoo, Devon, UK, June 2014. Model released.

Nick Upton / Volunteer Zoe Phillips placing a nest box with a Hazel dormouse (Muscardinus avellanarius) inside into a 'soft release' cage attached to a tree in coppiced ancient woodland, Nottinghamshire, UK, June....

Nick Upton / Volunteer Zoe Phillips placing a nest box with a pair of Hazel dormice (Muscardinus avellanarius) and an empty box inside a 'soft release' cage attached to a tree in coppiced ancient woodland, Notting...

Nick Upton / Gemma Keohane preparing food for Hazel dormice (Muscardinus avellanarius) ahead of release to a Nottinghamshire wood, Dormouse rearing facility, Paignton zoo, Devon, UK, June 2014. Model released.

Nick Upton / Volunteer carrying a nest box with a pair of Hazel dormice (Muscardinus avellanarius) and an empty box into coppiced ancient woodland to place them both inside a 'soft release' cage attached to a tree...

Nick Upton / Clare Stalford of the Wildwood Trust removing wire mesh from the entrance hole of a nest box containing a pair of Hazel dormice (Muscardinus avellanarius), held by Ian White, Dormouse officer for the...

Nick Upton / Lorna Griffiths of Nottinghamshire Wildlife Trust recording details of the Hazel dormice (Muscardinus avellanarius) that have been introduced to a 'soft release' cage in nest boxes within an ancient c...

Nick Upton / Ian White, Dormouse officer for the People's Trust for Endangered species holding a Hazel dormouse (Muscardinus avellanarius), Nottinghamshire, UK, June. Model released.

Nick Upton / Lorna Griffiths of Nottinghamshire Wildlife Trust inserting a feeding tube loaded with fresh fruit and seeds into a Hazel dormouse (Muscardinus avellanarius) 'soft release' cage before the nest boxes...

Nick Upton / Lorna Griffiths of Nottinghamshire Wildlife Trust providing young Hazel branches (Corylus avellana) as food and cover for a Hazel dormouse (Muscardinus avellanarius) 'soft release' cage before the nes...

Nick Upton / Wildlife trust staff and volunteers carrying nest boxes containing pairs of Hazel dormice (Muscardinus avellanarius) and empty boxes into the woods to place them inside 'soft release' cages attached t...

Nick Upton / Gemma Keohane taking a Hazel dormouse (Muscardinus avellanarius) from its tank to check and read its transponder chip code number ahead of release to a Nottinghamshire wood, Dormouse rearing facility,...

Nick Upton / Wildlife trust staff and volunteers carrying nest boxes containing pairs of Hazel dormice (Muscardinus avellanarius) and empty boxes into the woods to place them inside 'soft release' cages attached t...

Nick Upton / Ian White and Nida Al-Fulaij of the People's Trust for Endangered species and Lorna Griffiths of Nottinghamshire Wildlife Trust planning where to place nestboxes containing Hazel dormice (Muscardinus...

Nick Upton / Hazel dormouse (Muscardinus avellanarius) held in the hand of Ian White, Dormouse officer for the People's Trust for Endangered species, Nottinghamshire, UK, June. Model released.

Nick Upton / Mammalogist Gill Brown inspecting nest box set out for Common / Hazel dormice (Muscardinus avellanarius), in coppiced woodland near Bristol, Somerset, UK, October. Model released. Winner of the Doc...

Nick Upton / Two young Common / Hazel dormice (Muscardinus avellanarius), captured during a survey in coppiced woodland near Bristol, being held temporarily in a plastic sack, Somerset, UK, October. Non-ex.

Nick Upton / Ian Chambers and Gill Brown of Backwell Environment Trust returning a torpid Common / Hazel dormouse (Muscardinus avellanarius) to its nestbox after weighing it during a survey in coppiced woodland ne...

Nick Upton / Ian Chambers of Backwell Enviroment Trust lowering a nestbox containing a Common / Hazel dormouse (Muscardinus avellanarius) into a plastic sack held by Gill Brown, before taking measurements, in copp...

Nick Upton / Ian Chambers of Backwell Enviroment Trust holding Adult Common / Hazel dormouse (Muscardinus avellanarius) inside a plastic sack as Gill Brown inspects closely to sex it during a survey in coppiced wo...

Nick Upton / Mammalogist Gill Brown of Backwell Enviroment Trust using a spring balance to weigh a Common / Hazel dormouse (Muscardinus avellanarius) held in a plastic bag during a survey in coppiced woodland near...

Nick Upton / Mammalogist Gill Brown of Backwell Enviroment Trust finding a Common / Hazel dormouse (Muscardinus avellanarius) in a nest box in coppiced woodland near Bristol, Somerset, UK, October. Model released.

Nick Upton / Common / Hazel dormouse (Muscardinus avellanarius) being weighed in a plastic pot on a mini balance during a survey by Backwell Enviroment Trust in coppiced woodland near Bristol, Somerset, UK, Octobe...

Nick Upton / Data record sheet compiled by Backwell Enviroment Trust during a nest box survey of Common / Hazel dormice (Muscardinus avellanarius) in coppiced woodland near Bristol, Somerset, UK, October. Model re...

Nick Upton / Torpid Common / Hazel dormouse (Muscardinus avellanarius) found sleeping in a Dormouse nestbox set out by Backwell Enviroment Trust in coppiced woodland near Bristol, Somerset, UK, June.

Nick Upton / Torpid Common / Hazel dormouse (Muscardinus avellanarius) sleeping in a Dormouse nestbox set out by Backwell Enviroment Trust in coppiced woodland near Bristol, Somerset, UK, June. Winner of the Docum...

Nick Upton / Torpid Common / Hazel dormouse (Muscardinus avellanarius) sleeping while held in human hand during a survey by Backwell Enviroment Trust in coppiced woodland near Bristol, Somerset, UK, June. Model re...

Nick Upton / Torpid Common / Hazel dormouse (Muscardinus avellanarius) sleeping while being weighed during a survey by Backwell Enviroment Trust in coppiced woodland near Bristol, Somerset, UK, June. Winner of the...

Nick Upton / Nest of Common / Hazel dormouse (Muscardinus avellanarius) temporarily removed from nest box, held in hands during a survey by Backwell Enviroment Trust in coppiced woodland near Bristol, Somerset, UK...

Nick Upton / Adult Common / Hazel dormouse (Muscardinus avellanarius), held gently in human hands during a survey in coppiced woodland near Bristol, Somerset, UK, October. Model released. Non-ex.

Nick Upton / Adult Common / Hazel dormouse (Muscardinus avellanarius) captured during a survey by Backwell Enviroment Trust in coppiced woodland near Bristol, being encouraged to emerge from a nestbox placed tempo...

Nick Upton / Two young Common / Hazel dormice (Muscardinus avellanarius), captured during a survey in coppiced woodland near Bristol, being held temporarily in a plastic sack, Somerset, UK, October. Non-ex. Winner...

Nick Upton / Adult Common / Hazel dormouse (Muscardinus avellanarius), with good winter fat reserves, found in a nest box during a survey in coppiced woodland near Bristol, Somerset, UK, October. Non-ex.

Nick Upton / Young Common / Hazel dormouse (Muscardinus avellanarius) captured during a survey by Backwell Enviroment Trust in coppiced woodland near Bristol, being held temporarily in a plastic sack, Somerset, UK...

Nick Upton / Wood pigeon pair (Columba palumbus) courting on a lichen covered branch in late afternoon light, Gloucestershire, UK, April.

Nick Upton / Three Backwell Enviromental Trust volunteers coppicing young trees using hand saws and axes to increase biodiversity and to improve the woodland habitat for Hazel Dormice (Muscardinus avellanarius) ne...

Nick Upton / Backwell Enviroment Trust volunteer pushing over a young tree he has coppiced with a saw to increase biodiversity and to improve the habitat for Hazel Dormice (Muscardinus avellanarius) in woodland ne...

Nick Upton / Backwell Enviroment Trust volunteer coppicing young tree with a saw to increase biodiversity and to improve the habitat for Hazel Dormice (Muscardinus avellanarius) in woodland near Bristol, Somerset,...

David Kjaer / Common Dormouse (Muscardinus avellanarius) asleep in a person's hand. Bentley Wood, Wiltshire, May.

David Kjaer / Three Common Dormouse (Muscardinus avellanarius) sleeping in dormouse box. Bentley Wood, Wiltshire, May.

David Kjaer / Common Dormouse (Muscardinus avellanarius) sleeping with its tail over its head in dormouse box. Bentley Wood, Wiltshire, May.

David Kjaer / Common Dormouse (Muscardinus avellanarius) on blackberries, UK, Captive

David Kjaer / Common Dormouse (Muscardinus avellanarius) on blackberries, UK, Captive

David Kjaer / Common Dormouse (Muscardinus avellanarius) on blackberries, UK, Captive

David Kjaer / Common Dormouse (Muscardinus avellanarius) on blackberries, UK, Captive

George McCarthy / Common dormouse {Muscardinus avellanarius} foraging for hazelnuts, UK.

George McCarthy / Common dormouse asleep in nest with hazel nut {Muscardinus avellanarius} UK

George McCarthy / Common dormouse feeding on red berry {Muscardinus avellanarius} UK

Colin Varndell / Dormouse (Muscardinus avellanarius) climbing in wild cherry tree. Dorset, UK July.

Konrad Wothe / Hazel dormouse (Muscardinus avellanarius) nest among undergrowth, Bavaria, Germany. October.

Stephen Dalton / Common dormouse (Muscardinus avellanarius) hibernating in nest, Sussex, England, UK.

Bruno D'Amicis / Hazel dormouse (Muscardinus avellanarius) sitting on branch in forest undergrowth. Abruzzo, Central Apennines, Italy. September.

Colin Varndell / Dormouse (Muscardinus avellanarius) climbing in wild cherry tree. Dorset, UK July.

David Tipling / Hazel dormouse (Muscardinus avellanarius) held in hand during weighing, part of dormouse box checks to monitor dormouse populations. Kent. October.

Colin Varndell / Dormouse (Muscardinus avellanarius) climbing in wild cherry tree. Dorset, England, UK, July.