The grey squirrel (Sciurus carolinensis) was first introduced to Great Britain as an ornamental species for parks in 1876. Since then it has spread enormously to about 2.5 million animals and has replaced the smaller red squirrel (Sciurus vulgaris) in most parts of England and Wales; Scotland still has the largest population of red squirrels: The Forestry Commission published an estimation of 120,000 red squirrels, representing about 85 % of the UK red squirrel population, living in Scotland; 15,000 are living in England, 3,000 in Wales. To stop the grey squirrels' progression to the north a big culling scheme is planned to create a 25 kilometer wide corridor in the south of Scotland, which is free of grey squirrels, stretching from east coast to west coast.
How the Grey Squirrel Manages to Displace the Red Squirrel
The grey squirrel has several distinct advantages in comparison to its red cousin:
- It is bigger – about twice the size of a red squirrel, which means it also needs more food.
- It is less timid. Grey squirrels find it easier to live close to humans and in cities.
- It is less susceptible to stress than the red squirrels, who can suffer from reduced fertility when under pressure.
- It carries the parapox virus, but is not affected by it itself. The virus is lethal for red squirrels.
- It can eat a greater variety of food; for example it can handle bigger seeds and is able to digest acorns; it is less selective and also eats bark of trees. This also explains why grey squirrels can live in more dense populations, while red squirrels need more space and specific habitats to survive.
Red Squirrel Reserves Designed for Protection
The only safe haven for red squirrels is the Isle of Wight in the English Channel, which is free of grey squirrels. While the Isle of Wight has the sea as a natural barrier to protect red squirrels' habitats from grey invaders, creating reserves in other areas of Britain is more difficult for obvious reasons. There 16 reserves in the north of England, in Northumberland, Cumbria, Merseyside and North Yorkshire. To create supportive habitats it is important to secure woodland areas that are big enough to feed and shelter the squirrels. Coniferous forests, which have increased due to reforestation especially in Scotland, offer the best habitats for red squirrels; in broadleaf forests red squirrels need far more space to survive than grey ones.
Reasons for Culling Grey Squirrels
As the grey squirrel population spreads from south to north, stopping their progression at the planned buffer zone would give the Scottish red squirrels a chance to escape the lethal parapox virus. This is the most urgent reason for the culling scheme. Other reasons are sparing the red squirrels the competition about food and space and the stress that new grey neighbours automatically cause. Past culling projects seemed to prove effective, as red squirrels were observed to make a comeback to areas where they had already vanished.
The corridor is one of several projects of the organisation Red Squirrels in South Scotland (RSSS). While some animal rights activists speak out against any culling of animals, either native or introduced by man, other conservationists claim that apart from threatening their red relatives the grey squirrels cause a lot of damage to the British woodlands: as the species developed in the vast American forests, it is equipped with an insatiable appetite and stronger teeth that even destroy trees by stripping off the bark.
The complete elimination of the grey squirrel allover the UK would be a target for many conservationists, but is probably an unachievable goal.
Methods of Culling Squirrels
The usual method to kill grey squirrels, which are officially classified as vermin in the UK, is to catch them in traps and then kill them by a shot in the back of the heads. The use of poison like Warfarin, which causes a painful death by blood thinning, is legally restricted. Other ideas to generally control grey squirrels include spreading pellets for contraception control, but this needs more time to be developed and applied. But to protect the Scottish red squirrels from the lethal parapox virus, the immediate creation of a grey-free buffer zone is essential, says Environment Minister Mike Russell.
References and further information:
- Red Squirrels In South Scotland Project
- UK Red Squirrel Group of Scottish Natural Heritage
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Renate Oetjens - Renate Oetjens has been publishing on the internet for more than 14 years. After working for several German publishing houses and AOL ...
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