Grey squirrel fertility control









HRH The Prince of Wales, Patron of the Red Squirrel Survival Trust, hosted a reception at Clarence House on Monday 20 February for the United Kingdom Squirrel Accord, attended by leading British based environmental scientists and woodland and forestry experts. At the reception Lord Gardiner, Parliamentary Under Secretary of State, Defra, a strong advocate for the conservation of our native red squirrels and enhancing the UK’s native woodlands for the benefit and enjoyment of future generations, thanked His Royal Highness for his continued encouragement and leadership in the enterprise of protecting our native species. In doing so he celebrated the work of the National Wildlife Management Centre, part of the Animal and Plant Health Agency (APHA) who have been conducting research into fertility control for wildlife over the past 20 years. As a sign of the potential that Defra see in fertility control as a benign route to managing grey squirrel populations Lord Gardiner announced that Defra has contributed £39,000 of funding to enable APHA to carry out research into the feasibility of grey squirrel fertility control and establish the business case for longer term funding. He was also delighted to announce that this seed-corn of Defra funding has so far unlocked a further £125,000 for the project from charitable trusts and the private sector through the UK Squirrel Accord.


The problem

Grey squirrels cause serious damage to trees, stripping bark leading to stunted growth and ingress of disease and fungi, which in turn leads to loss of treescapes with their associated biodiversity and costs the forestry industry (industry sources estimate) tens of millions of pounds per year. Many English forestry businesses have as a direct result stopped planting native broadleaf species. Urban trees, which play a role in the management of CO2 and the absorption of particulates, are also damaged. Grey squirrels spread squirrel pox (100% fatal for red squirrels) and compete for food and this has led to the rapid decline of the native red squirrel in the British Isles. Trapping and shooting are labour intensive and will not succeed on their own in redressing this critical natural imbalance.


The work to be done

The development of an oral fertility control drug for grey squirrels, administered in bait by species-specific hoppers, would provide humane control with greater effectiveness and lower cost than other methods to industries related to the countryside. The target drug is already in use in injectable form in the USA and is effective in a wide range of species, including the closely related California ground squirrel. Preliminary laboratory research at APHA has shown that an orally delivered contraceptive can work. APHA has worked up a detailed research plan which aims to develop this work into a practical, widely accessible and affordable operational system. The APHA team involved is internationally renowned and widely experienced in fertility control.