Grey squirrels could be given contraceptives to control invasive species
The government is backing research into a contraceptive “pill” for gray squirrels in a bid to reduce the damage these rodents cause to Britain’s woodlands and the native red squirrel population.
This forms part of a multifaceted strategy against invasive species.
Officials will monitor pine martens reintroduced to Gloucestershire’s Forest of Dean following success in Ireland and Scotland and assess their impact on gray squirrel numbers.
Landowners are also encouraged to take action through grants for traps and support for trained volunteers managing non-native species.
The initiatives are part of updated government policy towards gray squirrels, whose population has reached 2.7 million in Great Britain since their introduction to North America in the 19th century.
They aggressively outcompete native red squirrels for food and transmit squirrel pox virus, which is fatal to reds but rarely fatal to grays.
The number of native red squirrels dropped to just 38,900 when they were pushed to Britain’s borders. Gray squirrels also damage woodlands by stripping tree bark; The economic cost of this destruction is estimated at £37 million per year in England and Wales.
In an update to the 2014 gray squirrel action plan, the Government said it would take action over the next five years, including encouraging landowners to take steps to control the animals with financial incentives and advice, and providing support for training on gray squirrel management.
The Department for the Environment (Defra) also said it would continue to support research into the development of an oral contraceptive delivered in a feeder accessible only to gray squirrels, as current control methods are often labeled “ineffective” and public support for non-lethal control has been published.
Pine martens, once common in British woodlands but largely extinct due to habitat loss and persecution, could also reduce gray squirrel numbers, officials said.
Forestry England will continue to monitor pine marten populations in forests and their impacts on gray squirrels, particularly following the Forest of Dean reintroduction project, which saw 35 pine martens reintroduced between 2019 and 2021.
Red Squirrel Recovery Network (RSRN) communications officer Heather Harris, from The Wildlife Trust for Lancashire, Manchester & Merseyside, said: “The Government’s new squirrel strategy rightly recognizes gray squirrels as a widespread non-native species and poses a serious threat to red squirrels and the health of woodland ecosystems.
“Red squirrels are now almost extinct in England, Wales and Northern Ireland, and are under serious pressure in Scotland. Without sustained and effective gray squirrel management, red squirrels could disappear from UK woodlands within 10 years.”
“The priority now must be to translate policy into coordinated, long-term action on the ground.”
And he said: “RSRN supports research into non-lethal fertility control led by the Animal and Plant Health Agency and funded by the UK Squirrel Pact and its supporters.
“This work remains in the research and development phase, where we will support landscape-scale trials of nutrient mechanisms to assess safety, effectiveness and practicality.”
