Keeping the door open for the dormouse - Veterinary Practice
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Keeping the door open for the dormouse

Our conservation correspondent takes a look at the falling numbers of dormice and efforts to keep them going.

THE COMMON (now there’s a
misnomer) or hazel dormouse is one
of those British mammals that most
people have heard of (courtesy of
Lewis Carroll), but probably never
had the pleasure of seeing in the wild.
Sadly, the chances of
the latter are decreasing
year on year as the
species continues to
decline nationwide.

The People’s Trust
for Endangered Species
charity has just released
a report stating that
dormouse numbers have fallen in
Britain by more than a third since the
year 2000, and that the species is now
extinct in 17 English counties. The
report goes on to say that now, more
than ever, the species is in danger of
disappearing completely from Britain.

It saddens me greatly when I read of
species in Britain that are under serious
threat. Britain is a rich country with a
considerable proportion of the human
population clearly interested in wildlife
and the environment, as demonstrated by the popularity of programmes such
as Spring Watch. If Britain struggles to
conserve any species, and in particular
an iconic species such as the hazel
dormouse, what hope is there for
endangered species in less wealthy countries around the

The problems
experienced by the
dormouse can largely
be explained through
loss of suitable habitat.
Dormice prefer
regenerating woodland such as occurs after coppicing or
the creation of “rides” or glades in
established woods. Coppicing used
to be a widespread practice but has
largely died out, meaning that prime
dormouse habitat has declined.

hedgerows and scrubland habitat are
also utilised and again there is now
much less of this available than in the
past. Populations can become isolated
and unable to repopulate woodlands
through lack of suitable hedgerow
“corridors” to spread along.

Hazel dormice are widespread
throughout northern Europe and
it is only in the north-west of their
range (Britain, Sweden, Denmark, The
Netherlands, Germany) that declines
seem to be occurring, probably due
to intensification of farming practices
and the aforementioned change in
woodland management. In Eastern
Europe and the Baltic States, numbers
appear to be stable.

Dormice are slow breeders, with
most females producing only one litter
per year of four young on average, and
which are typically born relatively late
in the year in July or even August. The
young need to reach a weight of 15-18
grams if they are to survive the winter
hibernation period.

Dormice are primarily nocturnal
and during the summer months
spend most of their time in trees and
shrubs, feeding on the flowers of oak,
sycamore, hawthorn and willow in the
early part of spring, and later on plants
such as honeysuckle and bramble.

Caterpillars, aphids and other
invertebrates are also eaten during the summer and, as autumn approaches,
blackberries and nuts such as hazelnuts
make up a significant part of their diet.
They rarely spend time on the ground
during this period and make typical
spherically shaped nests in the branches
of trees or brambles, most commonly
composed of the bark of honeysuckle.

Hibernation can begin in October
and last all the way through to May,
usually in a nest under the leaf litter or
in the bottom of a hedge. Because they
live at low population densities they are
not highly predated though some will
fall prey to stoats, weasels and owls in
the summer months and badgers and
wild boar may uncover them during the
winter while rooting in the ground.

The People’s Trust for Endangered
Species has been monitoring dormouse
numbers for over 25 years and is
actively involved in re-introduction
programmes and with educating
landowners on how they can best
manage wood and hedgerows to
encourage dormice to thrive. You can find out more by visiting their website

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