Facts and figures
See the web pages of many regional and local red squirrel groups.
Red squirrel distribution (UK)
UK Red squirrel distribution maps can be viewed at the National Biodiversity Network gateway (NBN).
Red squirrel distribution in Europe
Red squirrels occupy boreal, coniferous woods in northern Europe and Siberia, preferring Scots pine, Norway spruce and Siberian pine. In western and southern Europe they are found in broad-leaved woods where the mixture of tree and shrub species provides a better year round source of food (Gurnell, 1987). In the UK and Italy, broad-leaved woodlands are less suitable due to the better competitive feeding strategy of greys.
UK Red squirrels are now mainly present only in north England, south and central Scotland, Wales and Northern Ireland, mainly due to loss of habitat and disease. Grey squirrels are implicated in the transmission of Squirrelpox virus which is usually fatal to Reds. Population density varies geographically and also shows large annual fluctuations in response to tree seed crop availability. Densities can vary from 0.5 to 1.5 individuals per hectare. A series of years with poor seed crops may lead to a population decline.
Map of European red squirrel distribution © Societas Europaea Mammalogica 2010.
Red squirrels are timid, tree-dwelling mammals that live at low densities in the UK so are seldom seen. It is therefore very difficult to carry out an accurate census of the UK populations or assess population trends. The most recent estimates of red squirrel population size were compiled by (Harris et al. 1995). They produced an estimate of 161,000 red squirrels in Great Britain, with approximately 30,000 in England, 10,000 in Wales (although recent estimates are significantly lower), and a main population of 121,000 in Scotland, representing 70-75% of the GB population.
The population in England has a very fragmented distribution, occurring in isolated populations in the south of England, on the islands in Poole Harbour and the Isle of Wight, in the east, in Thetford forest, (although this population may already have disappeared) and across the north of England. The Welsh population is mostly confined to discreet woodland patches, predominantly in large coniferous forest blocks such as Clocaenog forest and on the Isle of Anglesey. Scotland is a stronghold for the red squirrel with a habitat that favours them over the grey squirrel such as the native Caledonian pine forests and the large sitka spruce-dominated conifer plantations. A survey in Northern Ireland gave a figure of 10,000 red squirrels across the province (O'Teangana, 1999).
It is thought that red squirrels made their way to the British Isles from mainland Europe by the end of the last ice age, approximately 10 000 years ago. Records indicate a large population as far back as the 15th and 16th Centuries, but evidence shows that before grey squirrel introductions, there were historical population fluxes of reds. By the 18th century populations were declining principally because of loss of woodland. Red squirrels were reported as extinct in some parts of Scotland following large-scale deforestation, but the widespread planting of conifers and introductions of red squirrels from England, and possibly Scandinavia in the late 18th and early 19th centuries resulted in increasing populations between 1890 and 1910.
In 1903, the Highland Squirrel Club was established to control red squirrels, which were causing severe bark-stripping damage to trees, and over 82,000 animals were killed in the 20 years up to 1933. Populations throughout the British Isles declined again between 1910 and 1930 becoming scarce in many places in the 1920's (Gurnell, 1991). A similar pattern of population change occurred in Northern Ireland.
Grey squirrel arrival
The grey squirrel was introduced to approximately 30 different sites in the UK between 1876 and 1929, and has contributed to the decline in red squirrel populations since 1920. Grey squirrels have now replaced red squirrel populations throughout much of their former range.
It is thought that when grey squirrels arrive in woodland populated by red squirrels, the two species can co-exist for about 20 years before red squirrels disappear. Throughout the whole of the UK, the red squirrel is still under threat from long term habitat loss and change, and from competition and potential grey squirrel incursion and disease transmission and it is predicted that their numbers will continue to decline, at least in mainland UK, without specific habitat management.