Our native red squirrels are now very close to extinction in the UK.
The reason for this is the introduction of the American grey squirrel during the 1870s. These were brought in by wealthy landowners who thought they might provide an entertaining alternative to our native reds. The grey squirrel has since spread rapidly, displacing our native reds due to the competitive advantage of its larger size and wider range of feed; but mostly because it carries a disease, the Squirrel Pox Virus, harmless to the grey squirrel but fatal to reds.
Red squirrels cannot survive for very long when in proximity to greys. But this is only part of a
much more serious problem.
It is regrettable that red squirrel conservation, for the time being, requires that grey squirrel numbers be controlled; giving the mistaken impression that this involves some sort of quality choice between red and grey. In reality, the conservation of red squirrels, despite its importance to us in the North, is a side-issue in a much wider ranging and more serious problem. The root cause of this is the very high grey squirrel population densities which can occur in UK woodlands resulting in catastrophic environmental damage; far greater than in their home woodlands in eastern United States, where numbers are limited by effective predators and food scarcity.
A particular concern is the grey squirrel habit of chewing the bark on trees, typically "ring-barking" branches of broad leaf trees approaching maturity. As can be seen in the above pictures taken by the Forestry Commission, this causes damage which may often result in either the death of the tree or a greatly increased susceptibility to disease. For this reason alone the planting of broad leaf trees in much of the UK is no longer economically viable. In short, we are losing an important commercial and strategic resource as well as beauty in our woodlands. The cost of this damage alone is currently estimated at close to £20M per year.
Grey squirrels also raid birds' nests, taking both eggs and fledglings, contributing to the precipitous decline in our songbirds. These problems are not unique to grey squirrels, for example red squirrels also chew bark, but it is because of the much larger population densities achieved by grey squirrels that the damage is so much more severe.
Also see the pamphlet by Red Squirrels Trust Wales et al. An updated report on grey squirrel damage in the National Forest has just been released and is featured in our News section. Planted just 25 years ago; sadly, this is now becoming quite seriously damaged. The report describes a 'text-book' example of just how serious and costly this problem can be.
We wholly accept that it's unjust to demonise our grey guests. They can be very charming and it's not their fault that they're here, but they're costing us dear!
Over the last 100 years grey squirrels have spread through most of the UK along with the loss of our red squirrels and significant degradation of our native woodland habitats. Until very recently, much to our shame, we've done precisely nothing to halt this.
But it doesn't have to be like this. As has been demonstrated over the last few years in the North of England,
effective control and monitoring has enabled our remaining reds squirrels to thrive. Also to re-colonize some areas where they had previously been lost to grey squirrel incursion and disease.
Whilst we can help red survival by controlling greys, this cannot reasonably be sustained over a long period or extended over the whole of the UK. We have to accept that most people have never seen a red squirrel. The grey squirrels in their gardens are all they know and they get great pleasure from them. For this reason, we need to be thinking about a more gentle, non-lethal process that would allow a gradual decline in the grey population, balanced by an increase in reds. The most promising approach is fertility control, i.e. a form of contraception for grey squirrels. This work, along with others, is described in our Research section.
There is now an increasing commercial and government awareness of the need for a practical grey squirrel control policy that meets with public acceptance and this is translating into investment and development. Assuming that this will deliver effective tools in the not too distant future, our task becomes the maintenance of a good residual red squirrel population until conditions allow a gradual re-colonization of their former habitats.