Squirrels in the UK
There are two species of squirrel in the UK; red squirrels and grey squirrels. Populations are currently estimated at approximately 140,000 red squirrels and 2.5 million grey squirrels. Red squirrels are our native species and have lived in the UK for around 10,000 years, Grey squirrels were introduced to the UK from North America by the Victorians in the 1800s, the first record of them escaping and establishing a wild population is 1876.
Why do red squirrels need protecting?
Grey squirrels are a familiar sight for many people across large parts of the UK and are often seen in parks and gardens, whilst the range of our native red squirrels is now limited to certain areas of the UK, such as Anglesey, parts of northern England and Scotland. In many cases they have retreated to wilder, remote locations. Many scientific studies show that the introduction of the grey squirrel has been the major factor in the red squirrel's decline over the past century, through competition for food and shelter and infection through the squirrelpox virus (which grey squirrels can transmit to red squirrels). Once infected with squirrelpox, red squirrels often die of starvation of dehydration within 1-2 weeks. Although grey squirrels can carry squirrel pox, their health is not impacted. Unfortunately, without conservation management, red squirrels could become extinct in England in approximately 10 years. Time is really running out to save our red squirrels.
To preserve red squirrels, they must be kept apart from grey squirrels as the two species cannot live together long term. The map below illustrates this as it shows that grey squirrels have replaced red squirrels across almost all of England and Wales.
How are The Wildlife Trusts helping?
The Wildlife Trusts has been at the forefront of efforts to save red squirrels for decades; undertaking habitat management to help red squirrels, education and awareness projects, monitoring of squirrel populations and targeted control of grey squirrels in areas where red squirrels are at risk of extinction.
The Wildlife Trusts is part of Red Squirrels United, a partnership of academics, practitioners and volunteers, working together on a programme of red squirrel conservation. It launched in 2015 and is focused on conserving red squirrel populations in nine specific areas in Northern Ireland, Northern England and Wales (see map below). Red Squirrels United also works closely with Saving Scotland's Red Squirrels to ensure that all parts of the UK are involved in red squirrel conservation. Working in partnership, Red Squirrels United enables red squirrels to continue surviving in these areas, and to spread out into some new areas where suitable habitat exists, alongside the remainder of the UK which is home to grey squirrels. Red Squirrels United is funded by EU LIFE14 (LIFE14 NAT/UK/000467) and The National Lottery Heritage Fund. The work undertaken by the programme includes education, public awareness, scientific monitoring, habitat management and grey squirrel control in carefully chosen target areas where red squirrels are at risk.
Frequently asked questions
Why can’t red squirrels and grey squirrels live together?
Grey squirrels compete more successfully than red squirrels for food and habitat. They are larger and more robust, and can digest seeds with high tannin content, such as acorns, more efficiently. This forces red squirrels into other areas where they can find it more difficult to survive. And, over time, grey squirrels ultimately replace red squirrels. This is illustrated in the map above which shows that red squirrels are now almost extinct in England and Wales. If the two species could live together long-term red squirrels would be more widespread throughout the UK mainland.
Grey squirrels also transmit a squirrelpox virus which can normally kill red squirrels. Once infected, red squirrels often die of starvation or dehydration within 1-2 weeks.
What are the main threats to red squirrels?
The grey squirrel is widely accepted as the main reason for the decline of the red squirrel over the past century. Habitat loss has also contributed to the red squirrel’s decline. Habitat loss and fragmentation occurs when areas of woodland are destroyed or become separated by development and changing land-use. This leads to isolated areas which cannot sustain viable populations of wildlife, including red squirrels in some places. The squirrelpox virus is fatal to red squirrels but is carried by grey squirrels without causing them any harm.
What is squirrelpox and what can be done about it?
This virus, carried by grey squirrels without causing them harm, is fatal to red squirrels and once infected red squirrels often suffer a slow and painful death. The virus produces scabs and sores in and around the eyes, nose, mouth, feet, ears and genitalia. The infected squirrel is very quickly unable to see or to feed properly and rapidly becomes dehydrated and malnourished. The disease is highly virulent in red squirrels and kills within 15 days of infection.
A vaccine against squirrelpox is in development but it could be many years before this is available in the affordable and easily dispensable form necessary to assist red squirrel conservation.
At this time, to protect red squirrels from infection with squirrelpox it is necessary to use targeted and co-ordinated grey squirrel control to keep densities of grey squirrel very low in carefully chosen areas.
Is this project part of a plan to eradicate grey squirrels from the entire UK?
No – this project is about maintaining the remaining red squirrels we have in parts of Northern Ireland and Wales and some parts of the north of England and expanding them in a few places in these areas to give some of the more isolated populations a better chance of survival.
The map above shows the project areas where Red Squirrels United is working (a separate project is carrying out similar work in Scotland).
Conservation management is targeted only to red squirrel stronghold areas and enables red squirrels to exist in these areas. This project is not working in the remainder of the UK which is still home to grey squirrels. Ultimately it means that both red and grey squirrels continue to exist in the UK although they must be kept apart as the two species cannot live together in the long-term, primarily because grey squirrels carry the squirrel-pox virus which kills red squirrels.
Does scientific evidence support red squirrel conservation including control of grey squirrels?
Yes - a large body of peer-reviewed scientific studies support the current approach to red squirrel conservation which can be summarised as awareness raising and education, habitat management and control of grey squirrels in carefully chosen areas to protect red squirrels.
In the UK, each country – Wales, Scotland, Northern Ireland and England – has a red squirrel strategy, approved by government and based on peer-reviewed science. All four of these strategies highlight grey squirrels as a main cause of red squirrel decline, and all advocate the control of grey squirrels in carefully chosen areas as a means to conserve at risk red squirrel populations.
Natural England is the the government's adviser for nature conservation in England. It's 'Review of red squirrel conservation activity in northern England (2009)' is the most comprehensive review of the science to date. It is based on more than 100 cited papers (click on the link above and scroll to p67-73), and says:
Whilst changes in land use, forest fragmentation and human impact may have locally played a part, there is no doubt that the main cause for the widespread disappearance has been competition by the introduced North American grey squirrel. In the absence of the grey squirrel, red squirrels would still be present throughout England in all woodlands of suitable composition and age structure as well as suburban areas, gardens and parks. (p7)
From the Welsh Government's 'Conservation Plan for Red Squirrel Conservation (2009)':
Conservation of red squirrel populations depends upon maintaining sites free of grey squirrels and ensuring a suitable habitat for sustaining red squirrels (p5)
From the Scottish Government's 'Scottish Strategy for Red Squirrel Conservation (2015)':
The benefits to red squirrels of reducing competition from grey squirrels are now more evident. Targeted grey squirrel control is now generally viewed as part of a long-term approach to achieving the Strategy aims.
From Northern Ireland's Red Squirrel Conservation Action Plan (1999):
Reasons for the decline of the red squirrel in the British Isles includes habitat loss and fragmentation and disease. However the most important factor appears to be competition with the introduced American grey squirrel.
These documents are based on a review and analysis of more than 100 papers on red squirrel ecology and feature contributions from more than 50 scientists, ecologists and organisations. Together they represent the most thorough assessment of science to date and all share the conclusion that until non-lethal management methods are available grey squirrel control in carefully chosen places is required to maintain populations of red squirrels.
Will grey squirrel numbers be controlled humanely?
The scientific evidence shows that if we are to prevent the extinction of the remaining red squirrels on the UK mainland and maintain viable populations numbers, there is currently no alternative to grey squirrel control in these areas. This is a last resort conservation measure and is only carried out by well-trained and monitored people, following Government guidelines for humaneness. Two methods are used after trapping: cranial despatch or shooting. A Government review of methods concluded that, of the options available, these were the most humane. This does not affect the vast majority of the UK’s grey squirrels which live outside areas for red squirrel conservation.
Are there any alternatives to controlling grey squirrels, like a vaccine or contraceptive?
Unfortunately no, not at the moment.
Contraceptive - a grey squirrel contraceptive is in development but it is likely to be at least five years until this is available for use and then further field research will be required for several years to establish whether this is sufficiently effective on its own. The development of a contraceptive is welcome but unless the current populations of red squirrels are maintained now through active conservation management, there will be no red squirrels left by the time a vaccine is available. Additionally, the current form of contraceptive relies on the development of a grey-squirrel-specific means of administering it as it would affect the fertility of red squirrels.
Squirrelpox vaccine – a vaccine against squirrelpox is in development but it could be many years before this is available in the affordable and easily dispensable form necessary to assist red squirrel conservation.
Habitat management – this is used in some places to help protect red squirrels. For example in areas with red squirrel populations, forestry guidelines recommend planting small-seeded broad leaved trees, like alder, around the boundaries to discourage grey squirrels, rather than large-seeded trees such as oak, which favour grey squirrels. Methods like these are in use but they have not been enough to prevent grey squirrel populations from expanding into many red squirrel refuges and the subsequent localised extinction of red squirrels.
Island translocation – the idea has been put forward to help red squirrels to retreat to island refuges around the UK where they would be safe. The main issues with this proposal are the loss of the majority of the population of red squirrels (only a few would remain) and the resultant loss of genetic diversity which would make the remaining island populations highly vulnerable. Many of the UK’s islands also currently lack the woodland habitat necessary for squirrels. Several of our larger wooded or partly wooded islands – Arran, Angelsey and the Isle of Wight for example - are already home to red squirrels. The Isle of Man has never been home to red squirrels – there are concerns that introducing them there could upset the island’s natural ecology where other species are already under pressure and in decline.
What happens if grey squirrels are not managed in places where they interact with red squirrels?
As the historic loss of red squirrels from much of Ireland, England, and Wales shows, non-intervention would lead to further loss of red squirrels ultimately ending in their extinction on the UK mainland. Evidence shows that without conservation management red squirrels are likely to become extinct in England within 10 years, and extinct in Scotland within the lifetime of today’s children (1). New research suggests this timeframe may be shorter.
Do pine martens help control grey squirrels?
Research by NUI Galway has shown that a high-density of Irish pine marten populations is causing corresponding populations of grey squirrels to collapse, with a recovery of red squirrels following. A new project has been launched by the University of Aberdeen to investigate whether the same effect is occurring in Scotland in areas where the pine marten is recovering, where differences in ecological conditions may make the outcome different to that in Ireland. The project will run until the end of 2017 and is led by Dr Emma Sheehy and Professor Xavier Lambin. This area of research is of interest but at the moment the fledgling recovery of the pine marten cannot be sole prospect for survival of our red squirrel due to its relatively low population densities.
The Wildlife Trusts are working with the following organisations to form Red Squirrels United: Newcastle University, Forest Research, The Wildlife Trust for Lancashire, Manchester and North Merseyside, Red Squirrels Trust Wales, Northumberland Wildlife Trust, Ulster Wildlife and The Wildlife Trust of South and West Wales.
Find out more about Red Squirrels United