Research has found that oral contraceptives for squirrels work, and the government hopes they can be used to keep populations in the UK.
Gray squirrels are an invasive species in the United Kingdom, introduced from North America in the 1870s. They pose a problem for wildlife, including endangered red squirrels, which they overcome. They also carry a disease called smallpox that does not affect them but can kill reds.
They were originally used as an ornamental species to decorate the gardens of stately homes, before the damage they caused was noticed and their release was banned in the 1930s.
Gray squirrels are also a threat to trees, as they strip their bark and weaken them. They are a particular problem for broadleaf varieties, including oak, which are ecologically important because they support so many other species. The UK is estimated to be home to some 3 million invasive rodents.
Scientists have been trying to find ways to reduce the gray population, and now the UK squirrel deal has released positive results after a test of oral contraceptives, which could be used to stop mammalian reproduction.
The contraceptive is produced by the Animal and Plant Health Agency (Apha), and additional tests are being conducted to ensure it is safe and effective.
To prevent other species from ingesting the drug, scientists have designed a special feeding hopper. It has a weighted gate that will exclude most other wildlife species while allowing more than 70% of local populations of gray squirrels to access and eat.
Apha is testing different methods to keep red squirrels out of feeders so that contraceptives can be placed in areas where there are both types of squirrels. So far, research suggests that body weight could be used to distinguish between grays and reds. No oral contraceptives have been used in the field at this stage of the research.
Environment Minister Richard Benyon said: “The gray squirrel is an invasive species that is causing incalculable damage to the British countryside, where these pests continue to destroy our broadleaf trees, such as oak, peeling the bark. and altering the delicate balance of nature and biodiversity, while diminishing our ability to cope with climate change.
“That’s why we continue to support the UK Squirrel Agreement and the Alpha, as this important research on oral contraception shows promising signs that could help eradicate the gray squirrel in the UK from a non-lethal way, as well as helping to recover our beloved red squirrel. ”
Other methods that have been used to try to reduce the number of gray squirrels include releasing pine martens to certain forests. These predators scare and eat gray squirrels. However, timid Tuesdays would not colonize urban areas that are red squirrel redoubts, so as long as forests continue to be covered by city gray squirrels, other methods, including contraceptives, will be needed to reduce populations.
Gideon Henderson, chief scientific adviser to the Department of the Environment, Food and Rural Affairs, said: “Fertility control can be an effective method that complements other approaches to wildlife management. This … study has aimed at producing an immunocontraceptive that can be administered orally to gray squirrels through a species-specific delivery mechanism.
“This innovative research has great potential to provide an effective, easy-to-apply and non-lethal method for managing gray squirrel populations. It will help red squirrels, native to the UK, to expand into their natural habitats.” in addition to protecting the UK’s forests and increasing biodiversity ”.