Ecology of the hazel
dormouse
People’s Trust for Endangered Species, 3 Cloisters House, 8 Battersea Park Road, London SW84BG
Registered charity no 274206
Cheeky Chappie Makes An Appearance In
A Fenland Garden Helping Himself To
Food!
November 2009
• Wood mouse
• Yellow neck
mouse
• Harvest mouse
• House mouse
• Field vole
• Bank vole
• Pygmy shrew
• Common shrew
• Water shrew
• Hazel dormouse
Class: Mammalia
Order: Rodentia
Family Muridae
Family Gliridae
Over 700 species including
mice, rats and gerbils
28 species of dormice
• Scaled tails
• Hop, climb or run
• Either herbivores or
omnivores
• Breed frequently
• Large litters
• Short-lived
• Furred tails
• Generally arboreal
• Nocturnal
• Omnivores; lack a caecum
• Breed once or twice a year
• Average litter of 4
• Long lived
• Hibernate
European Species
• Hazel dormouse – Muscardinus avellanarius
– European status: Least concern, Pop. trend: unknown
• Fat dormouse – Glis glis
– European status: Least concern, Pop. trend: unknown
• Garden dormouse – Eliomys quercinus
–
European status: Near threatened, Pop. trend: decreasing
• Forest dormouse - Dryomys nitedula
– European status: Least concern, Pop. trend: stable
• Mouse tailed dormouse - Myomimus roachi
– European status: Endangered, Pop. trend: decreasing
www.iucnredlist.org (2011)
What’s in a name?
• Common or Hazel dormouse
Muscardinus avellanarius
Mus – small brown animal
Scardinus – young edible dormouse
avellanarius – from hazel
Dormir – from french ‘to sleep’
• Fat or Edible dormouse
Glis glis
Glisere – latin ‘to grow’
Fat dormouse
• Non native
• Released 1902
• Size of small
squirrel
• Life cycle
linked to beech
• ‘Seven sleeper’
Hazel dormouse
• Native species
• Adult size: 50mm
body, wt 18-30+ g
• Furry tail
• Sandy coat develops
• Large black eyes
• Pads on feet
• Double-jointed hind
ankles
The hazel dormouse year
Breeding
Fully active
Short
periods of
activity
Young born
June
May
Young foraging
July
Apr
Aug
Second brood?
Sept
Mar
Frequent
arousals
Fattening up for
winter
Oct
Feb
Hibernating?
Occasional
arousals
Nov
Jan
Dec
Hibernating
The hazel dormouse year
Occasional
arousals
Frequent
arousals
Hibernating
Short
periods of
activity
Hibernating?
Fully active
Fattening up for
winter
Second brood?
Young foraging
Breeding
Young born
2010 Dormouse weight distribution by month,
adjusted by number of NDMP sites, where dormice
were recorded.
200
180
Frequency
160
140
April
120
May
100
June
July
80
August
60
Sept
40
Oct
20
Nov
0
0
2
4
Oct
6
8
10
12
14
August
16
18
20
22
24
Weight (grams)
June
26
28
30
32
34
April
36
38
40
Torpor and hibernation
• Latin – hiberna for
winter
• Hibernation – longer
than 24hrs
• Torpor – less than
24hrs
• Hibernate due to lack
of food in winter
• Torpor due to
inclement weather
Hibernation
• Minimum weight 15-18g
• November – April
• Hibernate in nests on
ground; moist, even
temperature
• Coppice stools, log piles,
leaf litter
• May wake/move
Torpor
• Occurs in active
period
• In nest boxes – with
and without nests
• Once disturbed will
wake
• 20mins to full
activity
Hazel dormouse diet
• Sequential feeders
• Lack caecum
• Nectar, pollen, seeds,
fruit, nuts,
invertebrates
• Food diversity needs
to be within home
range
Dormouse food requirements
Hazel
Buckthorn
Blackthorn
Ash
Oak
Birch
Hawthorn
Sycamore
Wayfaring
Elder
Dogwood
Yew
Honeysuckle
Bramble
May
June
July
August
Sept
Oct
Nests and breeding
• Range of distinctive
nests
• Breeding nest
woven covered with
green leaves
• Honeysuckle strips
and other local
material
• Usually more than
one nest
Dormouse breeding
• Males solitary
• First litters late May
• 4-6 young with
distinctive stages
• Occasional crèches
• May have second litter
• Population ‘boom’ in
Sept/Oct
The ages of Hazel dormice
Stage
Approx. age
Approx.
weight
Coat colour
Pinks
0 – 6 days
1 – 2.5g
Pink
Grey eyes closed
6 – 16 days
2.5 – 6g
Grey
Eyes open
16 – 28 days
6 – 10g
Grey or brown
Juvenile
(before first
hibernation)
28+ days plus
10g plus
Grey/sandy
Adult
(after first
hibernation)
8-12 months plus
12g plus
Sandy
Dormouse home range
• Adult male home range about 0.75 ha
Adult female range smaller
• Distance travelled a from nest
– Male 70m (Bright and Morris 1994)
– Female 50m (Bright and Morris 1991)
– Dispersing juvenile 376m (Wilder Wych 2011)
Dormouse population density
Species
Habitat
Mean Spring
density
Dormouse
Optimal – diverse wood with
abundant, vigorous understory
4 to 6 adults
Dormouse
Oak woodland with hazel
2 adults
Dormouse
Scrub
unknown
Dormouse
Conifer woodland
1 to 3 adults
Dormouse
Hedgerow
1.3 adults
Wood mouse
Deciduous woodland
40 plus
Bank vole
Deciduous woodland
100 plus
Dormouse predators
• Owls
• Grey squirrel
• Stoats, weasels
Between 40 – 70%
of dormice die in
hibernation
(Juskaitis 1977)
• Badger
• Wild boar
• Cats
Dormouse activity
•
•
•
•
•
Adapted for arboreal lifestyle
Use aerial pathways in tree/shrub canopy
Hazel – lax growth
Bramble – scrub banks
Reluctant to cross open ground (Bright and Morris
1992)
• But non-corridor habitat not complete barrier
to movement (Bright 1988, Buchner 1997, 2008)
Hazel
dormouse
distribution
(records from
1990-2013
Dormouse habitats
– Deciduous woodland with vigorous understory
• managed woodland
• managed coppice woodland
– Oak wood with hazel
• derelict coppice
– Scrub (connected?)
– Conifer wood
– Hedgerow
Dormice may be present in any wood or
scrub habitat within their range
Dormouse Ecology Summary
• Hibernate in nests at ground level
• Arboreal when active
• Exhibit torpor in inclement weather
• Sequential specialist feeders
• Live at low densities
• Small home range
• Low fecundity
• Long lived
Why are dormice
good?
• Key species
– Plant diversity
– Shrub structure
•
•
•
•
Woodlands
Hedgerows
Scrub
Responsibility
What’s good for dormice is good for
many other species
People’s Trust for Endangered Species, 3 Cloisters House, 8 Battersea Park Road, London SW8 4BG
Registered charity no 274206