Research has shown that oral contraceptives for squirrels are effective, and the government is hoping to utilize them to control squirrel populations in the UK.
Since being brought to the UK from North America in the 1870s, grey squirrels have become an invasive species. They are an issue for animals, notably red squirrels, who are in danger of extinction. Additionally, they are carriers of the disease squirrelpox, which can kill reds but has no effect on them.
Before the damage they caused was realized and their release was prohibited in the 1930s, they were initially utilized as a decorative plant to beautify the gardens of grand mansions.
In addition to being a threat to trees, grey squirrels degrade them by removing their bark. They pose a particular issue for broadleaf species, such as oak, which are crucial to the ecology because they provide habitat for numerous other species. Around 3 million of the invasive rodents are thought to reside in the UK.
A trial of oral contraceptives, which could be used to prevent the creatures from reproducing, has yielded promising results, according to the UK Squirrel Accord, which has been working to reduce the gray population.
The Animal and Plant Health Agency (Apha) is manufacturing the contraception, and additional research is being done to assure its efficacy and safety.
Scientists created a customized feeding hopper to prevent other creatures from consuming the drug. More than 70% of the local populations of grey squirrels can access and eat from them thanks to a weighted door that keeps out the majority of other wildlife species.
In order to use contraceptives in places with both types of squirrels, Apha is testing several techniques to keep red squirrels away of the feeders. Research to date reveals that greys and reds can be distinguished based on body weight. At this point in the investigation, no oral contraceptives have been used in the field.
“The grey squirrel is an invasive species that is causing untold damage in the British countryside, where these pests continue to wreck our fledgling broadleaf trees like oak by stripping bark and disrupting the delicate balance of nature and biodiversity, while reducing our ability to tackle climate change,” said environment minister Richard Benyon.
As a result, “we continue to support the UK Squirrel Accord and Apha since this critical oral contraceptive study offers encouraging indicators that could help remove the grey squirrel in the UK in a nonlethal fashion, as well as helping to recover our beloved red squirrel.”
Pine martens have also been released into specific woodlands as a means of attempting to lower the population of grey squirrels. Grey squirrels are scared away and eaten by these predators. While urban areas are strongholds for grey squirrels, shy martens would not settle there, necessitating the use of contraceptives and other control measures as long as woodlands are replenished by grey squirrels from the city.
The Department for Environment, Food, and Rural Affairs’ top scientific adviser, Gideon Henderson, stated: “Fertility control can be a useful strategy to support other approaches to wildlife management. The objective of this project is to develop an immunocontraceptive that can be given orally to grey squirrels using a species-specific delivery method.
This cutting-edge study has a tremendous deal of potential to offer a successful, practical, and non-lethal way for managing grey squirrel numbers. It will conserve UK woodlands and boost biodiversity while assisting native red squirrels to repopulate their original habitats.
Lead Image: Grey squirrels are an invasive species in the UK, originally brought in as ornamental animals to decorate the grounds of stately homes. Photograph: Niall Carson/PA. This article by Helena Horton was first published by The Guardian on 11 July 2022.
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