Scotland Ireland Great Britain Grey Squirrel (Sciuriscarolinensis) An Invasive To The U.K.
Physical Characteristics • The dorsal surface ranges from grizzled dark to pale grey and may have cinnamon tones • The ears are pale grey to white and its tail is white to pale grey. • Under-parts are grey to buff • The total length of these squirrels ranges from 380 to 525 mm • Tail length ranges from 150 to 250 mm
Reproduction • Breeding occurs in December-February and May-June and is slightly delayed in more northern latitudes. • Gestation lasts 44 days. • Most females begin their reproductive life at 1.25 years but can bear young as early as 5.5 months. • Females may bear young twice a year for more than 8 years. Grey Squirrels Competing to Mate
Litter Size • Newborns are naked • They weigh from 13-18g • Generally 2-4 young per litter (up to 8 young are possible)
Life Span/Longevity • The maximum longevity is 12.5 years in the wild • However, a captive female lived to be over 20 years of age.
Grey Squirrel Drey Drey: The proper name for a squirrel nest.
Native Habitat • The deciduous forests of North America.
Deciduous Forest • Deciduous: shedding of the leaves annually.
Introduction to the U.K. • The North American grey squirrel was deliberately introduced to Britain and other parts of Europe during the 19th Century. • Was released merely as a curiosity to satisfy the Victorian penchant for novelty. • Since then the adaptable and hardy grey squirrel has thrived in Britain’s parks, gardens and woodlands.
2008 Grey & Red Estimates • 5 million estimated number of grey squirrels in the UK. • 120,000 estimated number of red squirrels in the U.K. Red Dots= Current Red Squirrel Distribution Black Dots= Current Grey Squirrel Distribution
Grey Squirrel vs. Red Squirrel • The grey squirrel is able to out-compete the red in almost every phase of their life history. • It is also thought that the grey squirrel is more resistant to disease than the red . • The grey squirrel has now spread to occupy almost all of England with only the far north and a few more southerly areas as yet unoccupied
Grey Squirrel vs. Red Squirrel • Grey squirrels can weigh as much as 600 grams, twice that of an adult red squirrel. • Grey Squirrels live for an average of 7-9 years, compared to 6-8 years for reds. • They therefore have a significant physical advantage over the red squirrel. • In addition, having evolved in the oak and hickory forests of the north-eastern United States, grey squirrels also have several behavioral advantages over reds.
Grey Squirrel vs. Red Squirrel • The red squirrel, which is primarily arboreal and spends only 33% of its time on the ground. • The grey squirrel spends up to 80% of its time foraging on the woodland floor. • This adaptation means that, in the autumn, grey squirrels can increase their body weight by as much as 20% while reds, which feed far less efficiently in broadleaved woodland, rarely manage to gain 10% Poor Little Red Squirrel Big, Bad Grey Squirrel
Grey Squirrel vs. Red Squirrel • Neither grey nor red squirrels hibernate. • Both are therefore active throughout the winter months periods of extreme weather. • However, when they are forced spend several days in the drey without feeding, can have severe consequences for the red squirrel, which cannot store as much fat as the grey. • This deficiency is reflected in the fact that only 80% of young red squirrels survive their first winter and mortality remains as high as 50% in adults
Disease Between Species • In 1984 in East Anglia, a squirrel was found to be infected with a disease that was identified as a parapoxvirus. • This disease is fatal to red squirrels, but it is carried by the grey squirrel. Parapox Virus Red Squirrel with Parapox Virus
Economic Impact of Grey Squirrel • Grey squirrels, can cause significant damage to trees such as sycamore, beech, oak, sweet chestnut, pine, Norway spruce and larch, by bark-stripping. • This activity results in the death of only 5% of trees. • In 2000 it was estimated that squirrel damage reduced the value of commercially grown trees in the UK by £10 million (This is $20 million U.S. dollars.)
Some Economic Examples Wind-snap to 40-year old Norway spruce following grey squirrel bark-stripping damage Grey squirrel bark-stripping to main stem of sycamore Grey squirrel damage to 18-year old planted oak Fresh grey squirrel basal damage to beech
Ecological Impact • Grey squirrels may be partly responsible for recent declines in many woodland bird species. • They can exert this impact either through the predation of eggs and young chicks • They also take over nest sites and consume food such as seeds and nuts which would otherwise be exploited by birds. Grey Squirrel Eating A Bird Grey Squirrel Eating Duck Egg
Management Practices • Lethal control is governed by strict legal guidelines, but permission can be obtained to shoot, trap or poison grey squirrels to achieve the goals described previously. • The Forestry Commission currently spends £200,000 (This is $400,00 in U.S. dollars) per year controlling red squirrels, but they estimate that a great deal more would have to be spent for all of their serious impacts on British wildlife to be reversed.
Or You Could Get Yourself a Scotsman • “Armed with traps and air rifles, a team of nine squirrel protection officers will set to work in the Borders, supported, they hope, by members of the public.” • “Their aim will be to kill every grey squirrel in the south of Scotland within two years, to stop the animals spreading further north.” ~ The Scotsman Magazine~ http://thescotsman.scotsman.com/latestnews/Invading-grey-squirrels-face-mass.4305028.jp
So… Let’s Think About This!?! • Nine of Scotland’s elite officers will kill ALL five million squirrels within Two years. • So that would then mean that each individual man would have to kill and average of 762 squirrels per day, everyday for the next two years with no days off. • This can only happen however, if there is absolutely no reproduction
So… • Now, for an average person, this kind of job would be not only be physically exhausting, but mentally & emotionally as well. • But to a Scotsman this is just kiddy stuff.
“I never saw one walk -- and then suddenly, before you could say Jack Robinson, he would be in the top of a young pitch pine, winding up his clock and chiding all imaginary spectators, soliloquizing and talking to all the universe at the same time...” ~Henry David Throreau~
The Tale of Squirrel Nutkin “This is a Tale about a tail--a tail that belonged to a little red squirrel, and his name was Nutkin.” ~Beatrix Potter~