Securing Ireland’s Broadleaf Forests and Conservation
of Native Red Squirrels Through Integrated
Management of Grey Squirrels
(Combined Research and Inventory of
Squirrels in Irish Silviculture – ‘CRISIS’)
FINAL REPORT
JUNE 2008
Michael Carey, Forestry and Management Consultant, Project Manager
Geoff Hamilton, Wildlife Ecologist, Project Officer
CONTENTS
1Introduction......
1.1The CRISIS project
1.2CRISIS objectives
1.3Project Timeframe and Management
2Strategic context
2.1Irish Forestry
2.2Ireland’s broadleaf cover and broadleaf planting
3Squirrels - Background
3.1General ecology
3.2History of squirrels in Ireland
3.3History of squirrel damage to trees in Ireland and the UK
3.4History of grey squirrel control
3.5Red Squirrel Conservation
3.6Research
3.6.1Ireland
3.6.2UK and Italy
3.7Immuno-contraception research
3.8Irish Squirrel Survey 2007
3.9Squirrel pox virus
3.10Grey squirrel control options - Background
3.10.1Warfarin
3.10.2Trapping
3.10.3Shooting
3.11The European Squirrel Initiative
3.12Grants for squirrel control
3.13‘Black’ grey squirrels
4CRISIS Methodology – Promoting red squirrel conservation
4.1Involvement in the development of the All-Ireland Red Squirrel Species Action Plan
4.2Input into FEPS
5CRISIS methodology - Assessment of grey squirrel control options
5.1Site selection
5.2Damage assessments
5.3Grey squirrel control trials
5.3.1Warfarin hoppers
5.3.2Trapping
5.3.3Shooting
5.4Testing of trap designs
5.5CRISIS methodology – Public relations and education
5.5.1Public relations
5.5.2Education
5.6CRISIS methodology – Information gathering from third parties
5.6.1Interaction with third parties in Ireland
5.6.2Interaction with third parties in the UK
6CRISIS findings and outputs
6.1Effects of grey squirrel control upon tree damage
6.2Damage assessments in woodlands beyond original project sites
6.3Assessment of warfarin hoppers as a grey squirrel control option
6.4Assessment of live trapping as a grey squirrel control option
6.5Assessment of shooting as a grey squirrel control option
6.6Comparison of grey squirrel control methods
6.7Trap trial results
6.8Raising Public Awareness
7Conclusions
8Recommendations
8.1Summary of project recommendations
8.2Red squirrel conservation
8.3Monitoring of broadleaf plantations for damage
8.4Grey squirrel control using warfarin
8.5Grey squirrel control via trapping
8.6Grey squirrel control via shooting
8.7Proposed implementation of project recommendations on grey squirrel control
8.8Other recommendations
9Standard operating procedures – Methodology guidelines & photographs
9.1Trapping
9.1.1Trap design / recommended model
9.1.2Timing of control
9.1.3Trap operation
9.1.4Bait
9.1.5Laying traps
9.1.6Setting traps
9.1.7Dispatch
9.1.8Duration of trapping
9.1.9Licensing
9.2Shooting
9.2.1Timing
9.2.2Gun types
9.2.3Safety
9.2.4Licensing
9.2.5Gun club cooperation
9.2.6Squirrel calls and drey poking
9.3Poisoning with warfarin
9.4Red squirrel conservation
10References and further reading
11Appendices
11.1All Ireland Red Squirrel Species Action Plan
11.2Trap designs
1
Acknowledgements
A number of organizations and individuals were very helpful to the project team during CRISIS. These included Birdwatch Ireland, Coillte Teoranta, Crann, The Environment and Heritage Council Northern Ireland, The Heritage Council, The National Parks and Wildlife Service, The National Farmers Association, The Society of Irish Foresters, The Irish Timber Growers Association, The Forest Service, Northern Ireland, Woodlands of Ireland, Teagasc, The National Association of Regional Game Councils, and the Forestry Commission (UK) and the Red Squirrel Protection Partnership, Northumberland.
In particular the project team would like to express special thanks to the Forestry Inspectors (Forest Service), Jimmy Burke (Teagasc), Miles Barne (ESI), John Casey (Teagasc), John Connelly (Forest Service), Sandra Devaney (Dublin Zoo), Charles Dutton (ESI), Huw Denman (SelectFor), Cian McCormack (RTE), Michael McGoldrick (TCD), Ken Foley (JFK Arboretum), Janice Fuller, Margaret Gormley (OPW Phoenix Park), Tom Hayden (UCD), John Jackson (Irish Farmers Association), George Hipwell (Coillte), Irene Hughes (Ashbourne Community School), Geraldine Horgan (Dunshaughlin Community College), David Hutton Bury (Charleville estate), Andrew Kendall (ESI), Bernie Kiely (Forest Service), Eugene Hendrick (COFORD), Joe O’Carroll (COFORD), Morgan Kavanagh, Sean Keating (Teagasc), Liam Kelly (Teagasc), Colin Lawton (NUIG), Peter Lynch (Waterways and Wildlife Management), John Madden (Hilton Park), Ferdia Marnell (NPWS), Donal Magner, Barbara Maguire (Irish Farmers Association), Kim McColl, Peter Wyse Jackson (Botanic Gardens), Geoffrey Michael (JFK Arboretum), Ann-Marie MacMaster (Red Squirrel Conservation Officer, Dumfries and Galloway), Brenda Mayle (Forestry Commission, Alice Holt), Cameron Manson (Dalkeith estate), Keith Massey (Castlehoward estate), Frances McHugh (Teagasc), Favel Naulty (UCD), Pat Neville (Coillte), Kevin O’Connell (Teagasc), Paul Parker (Red Squirrel Protection Partnership), Andy Peters (Arpexas), Alistair Pfeifer (COFORD), John Pickard (Glendalough estate), Sean Rooney (Central Fisheries Board), Craig Shuttleworth (Anglesey Red Squirrel Project), Lord Redesdale, Gordon Robinson & Mark Wilkinson (Red Squirrel Protection Partnership), Michael Somers (Teagasc) Richard Wales (Red Squirrel Conservation Officer, Scottish Borders), Fiona Whitfield (Conservation Officer, Wildlife Trust, Lancashire), Andy Wiseman (Dalkeith estate), Douglas Wright (Forestry Commission, Scotland), John Rochford (TCD), Dick Scraible (NIFS), Karen Woods (Coillte), Keith Woolridge (Ballinacor estate) and Andy Verney (Lisnaveagh estate).
Special thanks also to the woodland owners in County Meath - Joe Barry, Phyllis Boyd, Edward Galvin, Ann Fanning, James Farrell, Michael Finnegan, the late Donal Murray, John Preston, Pat Raleigh, William Tracey and to Coillte Teoranta for access to Donadea Forest Park in Co Kildare.
1
Executive Summary
There are two species of squirrel in Ireland; the native red squirrel (Sciurus vulgaris) and the alien grey squirrel (Sciurus carolinensis). The grey squirrel was introduced at Castleforbes, Co Longford in 1911 and is now present in twenty-six counties on the island of Ireland. The spread of the grey squirrel is mirrored by a decline in the numbers of red squirrels and a contraction of its range; there may be as few as 40,000 red squirrels remaining in Ireland compared with an estimated number of 300,000 grey squirrels.
There are 152,000 hectares of broadleaf forest in the Republic of Ireland. Almost 93,000 hectares is owned by the private sector, a figure that is growing with increased farmer planting. One third or 28,000 hectares of the privately owned broadleaves has been grant aided over the past two decades. This represents a large investment by the State. Grey squirrels can be responsible for widespread damage to broadleaf trees through bark stripping, particularly in young woodlands as they pass from the thicket to pole stage. If not dealt with effectively, it has the potential to cause their destruction and undermine the State’s investment.
The Forest Service agreed in 2005 to fund a three-year project aimed at the conservation of the native red squirrel and the protection of the broadleaf estate in the Republic of Ireland through judicious management of the grey squirrel problem. The project was given the acronym ‘CRISIS’ meaning ‘Combined Research and Investigation of Squirrels in Irish Silviculture’. The project centered on ten privately owned woodland areas in County Meath and the Coillte woodlands at Donadea in County Kildare. It also included visits to other woodland areas known to have problems with grey squirrels in both Britain and Ireland. The development of strategies for the extension of the findings to other woodland areas, an educational programme for schools and other stakeholders based around the need to conserve the red squirrel from extinction and the raising of public awareness generally about the issues surrounding squirrels were also key objectives.
The results from the project show that serious damage can be done to broadleaf trees, notably beech, sycamore and oak by grey squirrels through bark stripping and that red squirrels can rarely co-exist and survive in the presence of a large grey squirrel population. However, if woodlands are constantly monitored effective action can be taken to ensure both their protection from grey squirrels and the enhancement of the habitat for red squirrels. This can be achieved through ensuring the tree species mix is conducive to the requirements of red squirrels and the implementation of effective action to control grey squirrels. Grey squirrels are at the greatest advantage over reds in woodlands comprised of large-seeded trees such as oak and hazel. In areas where it is hoped to protect the red squirrel, smaller seeded species such as ash, alder and various conifer species such Scots pine and Norway spruce are recommended.
A number of grey squirrel control measures used in both Britain and Ireland were tested. These included trapping of squirrels in cage traps followed by their humane disposal, the use of warfarin as a poison and finally shooting. The results showed that numbers can be effectively controlled using any of the three approaches. However, squirrels are likely to return to their previous levels if a sustained effort is not pursued and there is no cooperation between adjoining woodland owners. Although squirrel control using traps is time consuming and costly, it is preferred to the use of poisons such as warfarin, which may pose a risk to other species, notably red squirrels and pine martens. Anecdotal evidence suggests that the latter may be a natural predator on grey squirrels in some parts of the country, notably Cavan, Monaghan and in parts of the midlands. Shooting is also effective provided it is carried out with due care to safety issues. The active involvement of gun clubs at local level is strongly recommended as a means of control.
The results also confirm that the public generally empathises with the plight of the red squirrel and agree that action is needed to stem the threat posed by the grey squirrel.
In order to ensure an effective follow on to CRISIS the following course of action is proposed:
1.Establishment of a Red Squirrel Conservation Advisory Group chaired by the Forest Service.
2.Monitoring by woodland owners of their woodlands for the presence of grey squirrels and bark stripping.
3.The introduction of a trap loan scheme for grey squirrel control in key strategic areas by the Forest Service.
4.Realignment of planting and woodland management schemes in selected areas to reflect the needs of the red squirrel.
5.Circulation of an educational pack to all schools in the Republic of Ireland outlining the issues surrounding the conservation of the red squirrel and the protection of broadleaf woodlands from damage by the grey squirrel.
6.Collaboration with appropriate organizations in Northern Ireland.
1