On Tuesday 26 May 2026, King Charles visited the York Biotech Campus at Sand Hutton to meet the Animal and Plant Health Agency’s wildlife team and see work on an oral contraceptive designed to cut grey squirrel impacts and protect native red squirrels. The official announcement was brief, but it points to a live research programme that government and conservation partners are backing as part of red squirrel recovery. (gov.uk) What makes the project notable is its method. Rather than treating grey squirrel control as a choice between inaction and repeated culling, APHA is working on a targeted, non-lethal tool that could slow population growth and ease pressure on remaining red squirrel areas. (gov.uk)

Red squirrels are the UK’s only native squirrel and are classed as endangered. The UK Squirrel Accord puts the British population at roughly 287,000, with around 75% in Scotland, while Defra’s 2026 policy statement says England may now have just 38,900 left. (squirrelaccord.uk) Grey squirrels tell the other half of the story. They were introduced from North America from 1876 onwards, and current estimates put their British population at about 2.7 million. Forestry Commission guidance and Defra both say greys outcompete reds for food, displace them from habitat and spread squirrelpox, while habitat loss keeps the native species under extra strain. (gov.uk)

That explains why government is backing fertility control research. Defra’s grey squirrel policy statement, updated in February 2026, says current legal control methods are often viewed by land managers as work that must be repeated every year, and says public support exists for a non-lethal option. (gov.uk) The proposal is an oral immuno-contraceptive delivered through a species-specific bait hopper. In plain terms, the science is trying to create a feeder that grey squirrels will use regularly, while red squirrels and other wildlife do not get the bait. (gov.uk)

APHA’s own science blog shows the work has moved well beyond a concept note. Researchers say pilot laboratory trials achieved infertility in rats fed a contraceptive vaccine, and the team has also produced an immune response in captive grey squirrels. (aphascience.blog.gov.uk) Field testing has focused on delivery. According to APHA scientist Sarah Beatham, purpose-built feeders with weighted doors have already shown that bait can reach most grey squirrels in many woods with very limited access for other wildlife, and monitoring of 202 microchipped squirrels across six woods found average bait take of about 40 grams over most days in a four-day deployment. (aphascience.blog.gov.uk)

The hardest part is precision. APHA says the contraceptives under trial may affect other mammals, so feeder design matters as much as the vaccine itself. (aphascience.blog.gov.uk) Here the red squirrel protection work becomes especially concrete. Because red squirrels are smaller and lighter than greys, APHA has been testing an automatic weighing platform that opens only above a set body weight. Data gathered with volunteer groups in northern England and Wales suggest a threshold above the heaviest red squirrel could admit more than 90% of adult grey squirrels while keeping reds out, and a prototype test in Cumbria allowed only greys to reach the bait. (aphascience.blog.gov.uk)

This matters for more than one species. Forestry Commission guidance says grey squirrels strip bark, weaken stems, increase the risk of rot and disease, and in severe cases kill trees. The same guidance cites a 2021 Royal Forestry Society report estimating at least £1.1 billion in damage to woodland value in England and Wales over 40 years. (gov.uk) A workable fertility control tool would not replace habitat repair, local monitoring or volunteer action. It would be intended to sit alongside them, giving conservation groups and land managers another way to cut pressure on red squirrel areas and reduce repeated harm to young and maturing trees. (squirrelaccord.uk)

The remaining gap is the one every wildlife technology faces: moving from promising trials to approved, field-ready use. APHA says more work is still needed before the contraceptive is ready for registration and wider deployment. (aphascience.blog.gov.uk) That keeps the King’s visit in proportion. The public moment was useful, but the bigger story is patient conservation work: a native species under pressure, an invasive rival that is hard to manage by conventional means, and a research team trying to turn humane control into something that works in the real world. If that effort succeeds, it could make red squirrel recovery less fragile and easier to sustain across Britain. (gov.uk)