Key facts about red squirrels and grey squirrels and red squirrel conservation work undertaken by Wildlife Trusts, including the Red Squirrels United project.

Squirrels and Red Squirrels United – some key points

  • Two species of squirrels live in the UK today – red squirrels and grey squirrels.
  • There are 2.5 million grey squirrels and around 140,000 red squirrels.
  • Red squirrels have lived in the UK for around 10,000 years.
  • Grey squirrels were introduced from North America in 1876.
  • Grey squirrels are often seen in parks and gardens and are familiar to many people.
  • Red squirrels are now limited to certain areas of the UK and are much rarer
  • People care about their local squirrels – whether they are red or grey.
  • The red squirrel is in trouble and faces imminent extinction in some parts of the UK
  • The grey squirrel is widely accepted as the main reason for the decline of the red squirrel over the past century. This is because:
    - Grey squirrels compete with red squirrels for food and shelter and push them out to other areas
    - Grey squirrels carry the squirrelpox virus and transmit this to red squirrels. Once infected red squirrels die of starvation or dehydration over 1-2 weeks
  • Grey squirrels now occupy much of the UK but conservation management enables red squirrels to survive in some areas. Most of the UK’s red squirrels now live in Scotland.
  • Conservation management is targeted in areas where red squirrels are surviving but are at risk. This enables red squirrels to continue surviving in these areas, alongside the remainder of the UK which is home to grey squirrels
  • To preserve some red squirrels they must be kept apart from grey squirrels as the two species cannot live together in the long-term. The map below illustrates this as it shows that grey squirrels have replaced red squirrels across almost all of England and Wales.
  • Red Squirrels United is a partnership of academics, practitioners and volunteers working together on a programme of red squirrel conservation. It launched in 2015 and focuses on nine specific areas of red squirrel populations in Northern Ireland, Northern England and Wales.
  • Red Squirrels United involves the following organisations: Newcastle University, Forest Research, Lancashire Wildlife Trust, Red Squirrels Trust Wales, Northumberland Wildlife Trust, Ulster Wildlife and The Wildlife Trust of South & West Wales.
  • Work undertaken by the project includes education, public awareness, scientific monitoring, habitat management and control of grey squirrels in carefully chosen target areas where red squirrels are at risk.
  • Scientific evidence shows that control of grey squirrels in some key places where they are in contact with red squirrels is necessary in order to prevent the extinction of red squirrels in the mainland UK.
  • This is a last resort conservation measure and is restricted to a few, targeted areas. In the future, an alternative method of saving red squirrels may be available but unfortunately right now there isn’t one.
  • There is currently no available vaccine or contraceptive for grey squirrels, although research is being carried out to develop these. The current form of contraceptive could not be used in areas where populations of red and grey squirrels overlap as it would also affect the fertility of red squirrels.
  • Contrary to some reports there are no plans for a wide ‘cull’ of grey squirrels. As the map below shows Red Squirrels United operates in relatively few places and only where red and grey squirrel populations interact.
  • Evidence shows that conservation management can help red squirrel populations to recover

Learn more...

Red squirrels and grey squirrels

The red squirrel has lived in forests and woodlands across the UK since the end of the last ice age, 10,000 years ago, but their numbers have declined drastically over the last century and now there are approximately 140,000 left in the wild. Grey squirrels were introduced by the Victorians in 1876 and have since spread across much of the UK.

Many scientific studies show that the introduction of the grey squirrel from North America in 1876 has been the major factor in the red squirrel’s decline over the past century, both through competition for food and shelter and infection through the squirrelpox virus (which grey squirrels transmit to red squirrels). Unfortunately, without conservation management red squirrels will become extinct from the UK mainland - and extinct in England in around 10 years. Time is really running out to save our red squirrels.

This map shows the drastic decline of the red squirrel over the past century.

Red Squirrels United

The Wildlife Trusts and other conservationists have been involved in work to conserve the red squirrel for many years. Where grey squirrels are already established as the only squirrel species we are not taking action – the maps on this page show that the project is only active in a few areas so most of the UK is unaffected. The focus for Red Squirrels United is on protecting remaining red squirrel areas and creating viable populations. The project focuses on nine areas of red squirrel populations in Northern Ireland, Northern England and Wales. A number of organisations are involved including Wildlife Trusts in Wales, the north of England, Northern Ireland and Scotland. The project is supported by a range of organisations and governments around the UK.

This map shows the project areas where Red Squirrels United is working. The vast majority of the UK is unaffected

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. 

More about grey squirrels

Grey squirrels can be a joy to encounter in gardens and parks, and for many of us they are the only wild mammals we regularly see.

The grey squirrel evolved in North America and its introduction to the UK in the late 1800s has caused some disruption to our own wildlife. Species evolve together over many millions of years so the artificial arrival (introduced by people) of a new species can cause ecological problems. In the case of the grey squirrel this includes damage to trees which often concerns foresters, and loss of the red squirrel across most of England and parts of Scotland Northern Ireland and Wales which is often of concern to people who live near them, as well as conservationists.

In a few parts of the UK red and grey squirrels come into contact with each or might soon. Here scientific evidence has shown that action is needed to prevent the extinction of the red squirrel in the UK. The strategy for red squirrel conservation is about maintaining the remaining red squirrels we have in Scotland, parts of Northern Ireland and Wales and some parts of the north of England and expanding them in a few places to make some isolated populations more likely to survive. Red Squirrels United's work therefore does not have any impact on grey squirrels in most of the UK. There are no plans to eradicate the grey squirrel from the UK.

Ultimately red squirrel conservation work enables both squirrel species to live in the UK – but unfortunately the two species cannot live together in the same place in the long-term. We regret there is a need for control of any species but many years of study and experience have demonstrated that to save red squirrel from extinction in the UK control of grey squirrels is sadly necessary.

For more information

Visit the Red Squirrels United website at www.redsquirrelsunited.org.uk

(1) The changing patterns in the distribution of red and grey squirrels in the North of England and Scotland between 1991 and 2010 based on volunteer surveys - John Gurnell, Peter Lurz, Walter Bertoldi

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