The Red Squirrel

The red squirrel is one of Britain’s most endangered mammals. Under threat from habitat loss, non-native American grey squirrels and disease, its numbers are now a fraction of what they once were. Here we introduce Trees for Life’s exciting new project to help save this charismatic species. 


Everybody knows that squirrels eat nuts. But that’s not all! The seeds of trees such as Scots pine, oak, hazel and beech make up the main part of the red squirrel’s diet, but they also feed on a variety of other food types including buds, shoots, fungi, insects, beetles and birds’ eggs. They do not hibernate, but cache food supplies on which they feed throughout the winter.

Red squirrels are diurnal, meaning that they are active during the day. At night they sleep in a drey: a hollow ball of twigs and leaves that is built high in a tree and lined with moss, dried grass and hair. This is also where they raise young. Females can give birth to two litters per year, in the spring and autumn, and typically raise three young, known as kittens. 


Red squirrels were once found throughout the UK. Widespread deforestation in the 18th century destroyed much of their habitat, resulting in a huge decline in numbers. Although there was a subsequent increase between 1890 and 1910, large- scale culling over the next 20 years meant that by the 1930s red squirrels were scarce in many places.

During this time a new threat appeared: the non-native American grey squirrel. Grey squirrels were introduced to a number of sites and have since spread to colonise almost all of the UK. They are able to digest acorns more readily, meaning that in broadleaved woodland they easily out-compete their smaller counterparts, and they are also known to pilfer red squirrel food caches. Additionally, greys carry squirrelpox, a disease which does not affect them but is fatal to reds. Today, only 140,000 red squirrels remain, with three quarters of this population in Scotland and small pockets in north Wales and parts of England. 

What is being done to save them?

As grey squirrels are the current main threat to red squirrels, conservation efforts to date have focussed primarily on trying to control grey squirrel numbers. In Scotland, target zones for red squirrel conservation have been identified and greys are kept at bay around these areas. This strategy is working, but is a constant and ongoing challenge due to the size of the grey population south of the border.

Between 2004 and 2006 the Anglesey Red Squirrel Project released captive-bred red squirrels into Newborough Forest on Anglesey, creating a new wild population. Two years later, Trees for Life’s Patron, Roy Dennis, trapped 42 red squirrels from Moray and Strathspey and moved them to Dundonnell, in Wester Ross. This process is known as a translocation, and is a common tool in wildlife conservation. Subsequent monitoring of this new population has shown the translocation to have been extremely successful, with approximately 400 red squirrels now present. 

Trees for Life’s Red Squirrel Project

Following these successes, Trees for Life is about to begin an ambitious new project, in partnership with the Highland Foundation for Wildlife, Roy’s charity. Although Scotland holds three quarters of the UK’s red squirrels, many of these populations are isolated, and there are large areas of forest which are free from grey squirrels, that could provide an important refuge for reds. Over the next three years we plan to create ten new populations of red squirrels in the northwest Highlands, restoring this charismatic species to forests from which it has been missing for decades. 

Using humane traps baited with peanuts, we will catch red squirrels from areas where they are thriving. These trapping sites will be in areas that are free from grey squirrels, to ensure that we do not catch any that have squirrelpox. After a veterinary examination, they will be transferred into nest boxes, lined with hay and provisioned with apples and nuts, and carefully transported to the release site. The nest boxes will be secured to trees and the squirrels will be allowed to find their way out in their own time. We will provide them with peanuts through the first winter, to aid survival, and then the populations will be carefully monitored to measure breeding success and rate of expansion. Over the coming years we expect these populations to grow and potentially increase the Scottish population by more than 10%, which would provide a huge and much-needed boost to red squirrel numbers. 

Becky Priestley


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