I recall a grey squirrel control training session some 25 years ago, and being told that the measures we were shown – the use of bait laced with warfarin - might be useful for protecting trees on a small site, put pointless across the wider landscape. A toxic blood-thinner, warfarin sounded simply noxious, especially as it couldn’t prevent the poisoning of other animals. Therefore, the Government’s announcement last week (26th January) that they would support a programme of contraception to control and eventually eradicate grey squirrel from Britain raised many eyebrows, and caused me to cast a wry smile.
Its justification was wrapped in that usual nutshell of the impacts of invasive (read ‘non-native’) species on the British economy, an estimated £1.8 billion annual cost. Lord (Zack) Goldsmith said that the damage from grey squirrels also threatens the effectiveness of government efforts to tackle climate change through its tree-planting programmes to create “tens of thousands of acres of new woodlands.” The programme has the support from the Prince of Wales, who helped co-found the UK Squirrel Accord with the objective of "managing the negative impacts of invasive grey squirrels in the UK", along with a range of forestry, conservation and research organisations, including The Wildlife Trusts.
The proposal, following a pilot trial in Yorkshire, involves luring grey squirrels into feeding hoppers only they can access, containing little pots of hazelnut spread laced with an oral contraceptive. Results of studies so far suggest that in a small wood only a few days is required in summer to ensure the majority of grey squirrels access and consume the food that will ultimately contain the contraceptive. This non-lethal fertility control, ethically sounder than the other measures used so far, is currently subject to further research to assess its effective roll-out.