According to government scientists, the idea to utilize oral contraceptives to limit grey squirrel populations in the United Kingdom is progressing well and might soon be put to the test in field trials.
The plan for population control entails luring grey squirrels into feeding boxes they can only reach by using hazelnut spread-filled pots. These items will contain contraceptives.
Lord Benton, the minister for the environment, believes that the research could assist in the eradication of grey squirrels in the United Kingdom without the use of lethal methods.
It should lessen the “incalculable” harm caused by grey squirrels to forest ecosystems and red squirrel populations, he argues.
The contraception, which renders both male and female grey squirrels sterile, should be ready for deployment in the wild within two years, according to the government experts leading the project.
First brought from North America in the late 19th century, grey squirrels cause damage to British woodlands by peeling the bark from trees to access the rich sap beneath.
The species has thrived in the United Kingdom. There are currently estimated to be 2,7 million grey squirrels in this area.
The animals prefer broadleaf plants such as oak, beech, sweet chestnut, and sycamore, which they target when they are 10 to 50 years old.
They can kill or maim trees, leaving behind scarring that permits other tree pests and diseases to enter and hinder their development.
Lord Goldsmith, minister of the environment, has warned that the damage they might cause threatens the success of government efforts to combat climate change by planting tens of thousands of hectares of new forests.
Grey squirrels have also pushed the native red squirrel to the brink of extinction across a large portion of the United Kingdom.
It is estimated that there are about 160,000 red squirrels left in the United Kingdom, with approximately 15,000 in England.
Grey squirrels are substantially larger and stronger than red squirrels, and they carry a virus that is fatal to red squirrels but immune to them.
The traditional method for regulating the population of grey squirrels is through culling. However, grey squirrels reproduce swiftly and populations can rebound rapidly. The population has not been reduced despite a century of culling programs.
Contraceptives for squirrels
Dr. Giovanna Massei, the project’s main scientist from the government’s Animal and Plant Health Agency, thinks that dosing the animals with a contraceptive pill is a more humane and ultimately more effective alternative (APHA).
According to her, her team has produced a vaccination that stimulates the immune system to suppress the synthesis of sex hormones, rendering both male and female squirrels sterile.
The medicine is not permanent, and additional tests are being conducted to determine an effective and safe dose for usage in the wild.
In addition, the team has created a unique feeding hopper with a weighted door designed to exclude species other than squirrels.
Seventy percent of squirrels in each woodland visited the bait boxes over four days, with two enterprising mice being the only other creatures to gain inside.
The goal is to entice the hoppers with “irresistible” pots of hazelnut paste laced with the new contraceptive.
The scientists are also investigating the usage of specialized feeders in regions inhabited by both red and grey squirrels. These will be activated by a plate that weighs the animals and only grants access to the bait to the heavier greys.
Computer modeling, according to Dr. Massei, indicates that the contraceptive method could push grey squirrel numbers to the verge of extinction in some areas.
Dr. Massei explains, “It could even exterminate them from certain locations if coordinated control can be exercised so that they do not begin to re-immigrate.”
Dr. Massei believes that similar strategies might be used to manage the populations of other invasive species, such as rats, mice, deer, and wild boar if the work with grey squirrels is effective.
The UK Squirrel Accord (UKSA), a coalition of forestry and conservation organizations, is funding the research. It has gathered a little over $1 million to fund the project’s research and development.
The contraception program is a crucial supplementary non-lethal technique for managing grey squirrels, according to the UKSA’s director, Kay Haw.
“Red squirrels currently only exist in island habitats where there are no grey squirrels or where a red squirrel community group is actively striving to keep grey squirrels at bay,” she explains.
The annual damage caused by grey squirrels is estimated to cost £37 million in England and Wales alone. The cost to biodiversity in the United Kingdom has not been calculated.
A mature oak tree can provide habitat for up to 2,000 additional species.
Prince of Wales, who was key in establishing the UKSA, is among those who endorse the project.
People for the Ethical Treatment of Animals support non-lethal population control methods if it becomes necessary to implement population control.
However, the report advises, “We must not forget that grey squirrels and other “invasive” species are in their current locations due solely to human irresponsibility, and they deserve to be left alone.”
Chris Packham, a broadcaster and naturalist, considers a species-specific oral contraception a “dream ticket” if it proves to be economically viable and practicable.
He described the project as “non-violent direct action” to control “a broad and extraordinarily abundant invasive animal” and advises that an attempt be made to reintroduce pine martens to their former habitats across the country.
It has been demonstrated that these predatory mammals – a native UK species that have historically been persecuted – reverse the spread of invasive grey squirrels in Scotland and Northern Ireland.
