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Forest Research home > Research > Protecting trees > Reducing the impact of non-native or invasive vertebrates to forestry > Management of non-native or invasive vertebrates

Management of grey squirrels

Summary

Grey squirrel on Oak tree
Red and grey squirrel distribution from 1998 data
Red and grey squirrel distribution map for UK and Ireland from 1998 data
Enlarge map (600x732px : 43K)
Enlarge map (large) (1368x1668px : 79K)
Map showing the most up to date distribution

Since their introduction into Britain between 1876 and the 1920’s, grey squirrels have spread rapidly, gradually displacing the native red squirrel in most of England and Wales, and in central and south-east Scotland.

Grey squirrels are extremely destructive in woodlands, stripping bark from the main stem and branches of trees. Increasingly, wider impacts of grey squirrels are being recognised as of potential major significance to woodland conservation, biodiversity and sustainability.

Research objectives

The overall aims of this research programme include:

  • Investigating the impact of grey squirrels on woodland biodiversity and identify efficient control strategies
  • Developing cost effective methods of managing impacts on timber production
  • Developing a decision-support system to provide guidance to woodland managers on targeting grey squirrel control to support sustainable forest management
  • Promoting and supporting best practice management for the control of grey squirrels and their impacts.

Specific objectives include:

  • Support evidence based policy development at national and regional levels
  • Develop methods of predicting grey squirrel damage to improve the targeting of control by gaining a better understanding of the relationship between squirrel population dynamics, habitat structure and bark stripping damage
  • Assessing impacts of the introduced grey squirrel on sustainable woodland management
  • Investigating competition with native mammals such as the red squirrel and common dormouse and predation on woodland birds 
  • Investigating indirect impacts on woodland structure through seed predation and bark stripping influences on tree growth and stand structure
  • Investigating novel and develop improved methods of population control, including reviewing the potential use of attractants
  • Monitoring developments (worldwide) in the use of immuno-contraceptives for mammal population control, and consider their potential application to grey squirrel control (see reproductive inhibition in grey squirrels)
  • Determining the effects of grey squirrel damage on timber quality and develop cost benefit analysis for control of damage in broadleaf and conifer woodlands
  • Investigating alternative methods of damage limitation such as stand management, and the development of physical and chemical deterrents
  • Providing practical advice to the forest industry and the general public and promote best practice by supporting training seminars and workshops on grey squirrel control for woodland owners and managers.

Funders and  partners

Forestry Commission logo
This research is funded by the Forestry Commission Vertebrate management programme. This includes an annual summary of the research.

Further reading

Forestry Commission and other publications covering the management of grey squirrels. Some are available for downloading.

Status

The programme is on going. 

Contacts

Project Manager

Dr Robin Gill

For general enquiries and advice on grey squirrel control 

Mark Ferryman