|
| |
Red Squirrel ( Redmond Squirrel
)
For the North American Red Squirrel see
American Red Squirrel
The red squirrel (Sciurus
vulgaris), is a one of the most common
species of
tree squirrels (genus
Sciurus). Red squirrel are
tree-dwelling
omnivorous
rodents that are frequently found throughout
Eurasia but has been widely replaced by the
eastern gray squirrel in
Britain.
Physical description
Red Squirrels have a typical head
to body length of 19 to 23
cm, a tail length of 15 to 20 cm and a mass of 250 to 340
g, they are not
sexually dimorphic as males and females are the same size. The Red Squirrel
is slightly smaller than the
Eastern Grey Squirrel which has a head to body length of 25 to 30 cm and
weighs between 400 and 800 g. It is thought that the long tail helps the
squirrel to balance and steer when jumping from tree to tree and running along
branches and may keep the animal warm during sleep.
The coat of the red squirrel
varies in colour with time of year and location. There are several different
coat colour morphs ranging from black to red. Red coats are most common in
Great Britain, in other parts of Europe and Asia the different coat colours
co-exist within populations, much like hair colour in humans. The underside of
the squirrel is always white-cream in colour. Red Squirrels shed their coats
twice a year, switching from a thinner summer coat to a thicker, darker winter
coat with noticeably larger ear-tufts (a prominent distinguishing feature of
this species) between August and November. A lighter, redder overall coat colour,
along with the larger ear-tufts helps to distinguish the European Red Squirrel
from either of the Eastern Grey Squirrel or the American Red Squirrel.
The Red Squirrel, like most tree
squirrels, has sharp, curved
claws to enable the climbing of trees, even when branches are overhanging.
Reproduction and mortality
Mating can occur in late winter
during February and March and in summer between June and July. Up to two litters
a year per female are possible. Each litter usually contains three or four young
although as many as six may be born.
Gestation is about 38 to 39 days. The young are looked after by the mother
alone, and are born helpless, blind and deaf and weigh between 10 to 15 g. Their
body is covered by hair at 21 days, their eyes and ears open after three to four
weeks, and they develop all their teeth by 42 days. The juvenille Red Squirrel
can eat solids around 40 days following birth and from that point can leave the
nest on their own to find food, however they still suckle from their mother
until
weaning occurs at eight to 10 weeks.
During mating, males detect
females that are in
œstrus from an odor that they produce, and although there is no courtship
the male will chase the female for up to an hour prior to mating. Usually
multiple males will chase a single female, until the dominant male, usually the
largest in the group, mates with the female. Males and females will mate
multiple times with many partners. Females must reach a minimum body mass before
they enter œstrus, and heavy females on average produce more young. If food is
scarse breeding may be delayed. Typically a female will produce her first litter
in her second year.
The lifespan of the Red Squirrel
is on average three years, although individuals may reach seven years of age,
and 10 in captivity. Survival is positively related to availability of
autumn–winter tree seeds, on average, 75 to 85% of juveniles disappear during
their first winter, and mortaility is approximately 50% for winters following
the first.
Ecology and behaviour
The Red Squirrel is native to
usually
coniferous forest and it is also found in
temperate broadleaf woodlands. The squirrel makes a nest, known as a
drey in a branch-fork of a
conifer by laying down twigs to make a domed structure about 25 to 30 cm in
diameter, then lining it with
moss, leaves, grass and
bark. Hollows and
woodpecker's nests are also used. Red Squirrels are solitary animals and are
shy and reluctant to share food with others. However, outside of the
breeding season and particularly in winter, multiple Red Squirrels may share
a drey to keep warm. Social organization is based on dominance hierarchies among
and between sexes, although males are not necessarily dominant to females, the
dominant animals tend to be larger and older than subordinate animals and
dominant males tend to have larger home ranges than subordinate males or
females.
Red Squirrel
Red Squirrels eat mostly the
seeds of trees, neatly stripping conifer cones to get at the seeds within.
Fungi, birds'
eggs,
berries and young shoots are also eaten. Often the bark of trees is removed
to allow access to
sap. Between 60% and 80% of active period may be spent foraging and feeding.[3]
Excess food is put into caches, either buried or in nooks or holes in trees and
eaten when food is scarce. Red Squirrels do not remember where they created
caches; they have to search for them when in need, and many caches are never
found again. No territories are maintained, and the feeding areas of individuals
overlap considerably.
The active period for the Red
Squirrel is in the morning and late afternoon-evening. They often rest in their
nests in the middle of the day, avoiding the heat and the high visibility to
birds of prey that are dangers during these hours. During the winter, this
mid-day rest is often much more brief, or absent entirely, although harsh
weather may cause the animal to stay in its nest for up to days at a time.
Arborreal predators include small
mammals including the
Pine Marten,
Wild Cats, and the
Stoat which preys on nestlings, birds including
owls and raptors such as
Goshawk and
Buzzard may also take Red Squirrels. The
Red Fox, cats and dogs can predate upon the Red Squirrel when they are on
the ground. Humans influence the population size and mortality of the Red
Squirrel by destroying or altering habitats, causing road casualties, or through
controlling populations by hunting.
The Eastern Grey Squirrel appears
to be able to out-compete the Red Squirrel for various reasons:
- The Eastern
Grey Squirrel can easily digest
acorns, while the Red Squirrel cannot.
- The Eastern
Grey Squirrel carries a disease, the
parapox virus, that does not appear to affect their health, though will
kill most red squirrels.
- When Red
Squirrels are put under pressure, they will not breed as often.
It is worth noting that Eastern
Grey Squirrels do not usually attack Red Squirrels, and direct violent conflict
between these species is not a factor in the decline in Red Squirrel
populations.
|
This
web site is best viewed when your monitor is set at 1024 X 768