Red Squirrel Recovery Network (RSRN)

Red squirrel numbers have declined sharply over the past century due to several pressures. The introduction of non-native grey squirrels has had the greatest impact, as greys compete for food and habitat and also carry the squirrelpox virus, which is fatal to reds. At the same time, the loss and fragmentation of woodland have reduced suitable areas for them to survive. Once widespread across the UK, red squirrels are now mainly limited to Scotland, northern England, Ireland, and some isolated areas where they are carefully protected. Conservation projects are helping to protect remaining populations, but the species remains at risk in much of its former range.

Grey squirrels were first introduced to England from North America in 1876 as an ornamental species to populate the grounds of stately homes. Around 30 separate introductions occurred until 1930 when the damage caused by the grey squirrel was recognised and it was made illegal to release a grey squirrel to the wild. Grey squirrels have rapidly spread and colonised much of mainland England with detriment to our native red squirrel. The most significant threat associated with grey squirrels is the spread and transmission of a disease called squirrelpox virus (SQPV). It can take only one grey squirrel to introduce this virus to a local population of red squirrels and then the virus can spread throughout the reds with devastating effect. Where a grey squirrel introduces SQPV, red squirrel population decline has been observed at between 17-25 times quicker than through competition alone. Grey squirrels will also out-compete red squirrels for food, as they are able to eat nuts and seeds before they ripen, whilst reds can’t, leaving them with less available food.

Yes. The squirrelpox virus is most often introduced to red squirrel populations through contact with grey squirrels, who can carry the virus without becoming seriously ill. Transmission can happen directly through close contact or indirectly via contaminated surfaces such as feeders, food sources, or shared nesting areas. Once the virus is present in a group of red squirrels, it does not rely on grey squirrels to spread further. Infected red squirrels can pass it on to others, allowing the disease to circulate within the population. This makes outbreaks particularly serious, as the virus is usually fatal to reds and can cause rapid local declines once established.

At present, there's limited evidence suggesting red squirrels are evolving resistance. Research continues, but immunity within wild red populations remains extremely low, and outbreaks are typically severe.

Complete removal of grey squirrels from the UK is unlikely. Since their introduction in the late 19th and early 20th centuries, grey squirrels have spread widely and now occupy most of England, Wales, and parts of Scotland. Their ability to reproduce quickly and adapt to a variety of woodland habitats makes eradication impractical on a national scale. However, local management can make a significant difference. In areas where grey populations are controlled, red squirrels are able to recover and maintain stable numbers. Targeted control, combined with habitat management and community involvement, is therefore a key part of conservation strategies to protect remaining red squirrel populations.

Research indicates that pine martens, medium-sized predators native to the UK, may play an important role in supporting red squirrel conservation. Studies show that pine martens seem to prey more frequently on grey squirrels than on reds. Grey squirrels are larger, slower, and spend more time on the ground, making them more vulnerable to predation. Red squirrels, in contrast, are lighter, quicker, and more arboreal, which helps them avoid being targeted as often. Red squirrels also co-evolved alongside the predator resulting in an natural instinct to avoid them. Pine martens are currently being reintroduced across the UK following large-scale persecution of the species.

Yes. While culling has been the most common method of controlling grey squirrel numbers, researchers and conservationists are exploring alternative approaches. One option under investigation is the use of oral contraceptives delivered through bait, aiming to reduce grey squirrel reproduction. It is hoped the contraceptive will be ready for delivery within a decade. Another approach being looked into is the use of genetic technologies such as gene drives to limit population growth over time, though this is not yet close to practical application.

In addition to direct population control, habitat management can also play a role. Woodlands dominated by Scots pine or conifer species tend to favour red squirrels, which are better adapted to these habitats than greys. Creating or maintaining such environments can help give reds a competitive advantage.

Both habitat loss and competition from grey squirrels present significant challenges to the survival of red squirrels, but their impacts vary depending on location. In areas where grey squirrels are already established, they generally pose the greater threat. Grey squirrels not only compete directly with reds for food and space but also carry the squirrelpox virus, which is often fatal to red populations.

Nevertheless, habitat loss and fragmentation remain serious long-term concerns. Red squirrels depend on well-connected, high-quality woodlands to move, forage, and establish stable populations. Without suitable habitat, even areas free from grey squirrels may struggle to support sustainable numbers of reds.

For this reason, effective conservation requires a dual approach: managing grey squirrel populations while also protecting, restoring, and connecting woodlands. Both actions are essential if red squirrels are to recover and thrive across more of their former range.

Long-term coexistence between red and grey squirrels in the same woodland is extremely uncommon. Grey squirrels are generally larger and more efficient at exploiting food resources, particularly in broadleaf woodlands where acorns and other large seeds are abundant. This competitive advantage usually results in reds being displaced over time.

The threat is worsened by the spread of the squirrelpox virus, carried by grey squirrels without ill effects but often fatal to reds. Even when food resources are sufficient, the presence of the virus can cause rapid declines in red populations, eventually leading to their disappearance from affected areas.

There are, however, some circumstances where reds fare better. Conifer-dominated woodlands, such as those found in parts of northern England and Scotland, tend to favour red squirrels. Reds are more efficient at feeding on smaller conifer seeds than greys, giving them a competitive edge in these habitats. For this reason, the conservation and management of conifer woodlands play an important role in sustaining red populations in regions where greys are present.

You can support red squirrels by reporting sightings, volunteering with local conservation groups, planting squirrel-friendly trees, and avoiding feeding grey squirrels. How you can help.

If you find an unwell or injured red squirrel, do not try to handle it. Contact a local wildlife rescue or conservation group immediately. Quick reporting can sometimes help contain disease outbreaks or potentially save the animal.