Red squirrels

It is widely established that the introduction of the invasive non-native grey squirrel from North America to Ireland in 1911 has led to the drastic decline in red squirrels - see map. 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. As a result, grey squirrels are regarded as 100 of the World’s Worst Invasive Alien Species.

This lethal 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.

The killing of any wild animal is always a last resort measure to deal with serious conservation management problems and is only considered where there is strong evidence that this will be effective in achieving conservation objectives.

The methods we have adopted follow the strictest standards for humaneness, according to British and European Guidelines, and any control programmes are carefully targeted and scientifically monitored. Our methods are also supported by the European Scientific Panel on Animal Health and Welfare.

No. At this time halting further spread of grey squirrels at strategically targeted points is the only viable option to protect remaining strongholds for red squirrels. Habitat improvements can assist red squirrels to do better than grey squirrels in carefully chosen areas.

Grey squirrel contraception is the subject of research, but this is a long way from being ready for use and may be insufficient on its own. 

Visit the UK Squirrel Accord page to find out more about the current status of the research on fertility control.

Research by the National University of Ireland and Queen’s University Belfast has demonstrated that recovery of Irish pine marten populations can cause populations of grey squirrels to collapse, with a complete recovery of red squirrels following rapidly. We have evidence that this phenomenon is likely to be occurring across large areas of Ireland, including in Co. Fermanagh.

The 2019 All-Ireland Survey demonstrated pine marten range expansion and grey squirrel range contraction in many parts of the island in the past decade. Encouragingly, red squirrels are now reoccupying many formerly deserted sites.

However, we cannot allow the recovery of the pine marten to be the sole prospect for the survival of our red squirrel; in many areas, Pine marten densities remain low and below the levels, which seem to be required to cause grey squirrel population collapse. Moreover, it is considered unlikely that pine marten will ever reach sufficient densities in urban areas to completely remove all grey squirrels.

Pine marten recovery can also create challenges for humans such as using attics for dens or killing poultry. Ulster Wildlife recognises these issues and seeks to provide effective solutions. For more information, visit PineMarten.ie or the DAERA website