Scientists design contraceptives to restrict grey squirrels

a red squirrel eating some corn in a forest

The UK’s native pink squirrel – pushed near extinction by invasive grey squirrels

A plan to make use of oral contraceptives to manage grey squirrel populations within the UK is making good progress and will quickly be put to the check in area trials, authorities scientists say.

The mass contraception plan includes luring grey squirrels into feeding containers solely they will entry, utilizing pots containing hazelnut unfold. These can be spiked with contraceptives.

The challenge may assist eradicate the grey squirrel within the UK with out killing them, says surroundings minister Lord Benyon.

It ought to scale back the “untold harm” grey squirrels do to woodland ecosystems and native pink squirrel populations, he says.

The federal government scientists main the analysis say the contraceptive, which makes each female and male grey squirrels infertile, must be able to deploy within the wild inside two years.

Grey squirrels, first launched from North America within the late nineteenth century, harm UK woodlands by stripping bark from bushes to get on the nutritious sap beneath.

The species has flourished within the UK. There at the moment are reckoned to be 2.7 million grey squirrels right here.

The animals goal younger bushes, sometimes 10-50 years outdated, and favor broadleaf species together with oak, beech, candy chestnut, and sycamore.

They will kill or maim bushes, leaving scarring that permits an entry level for different tree pests and illnesses which may stunt their progress.

The harm they will do threatens the effectiveness of presidency efforts to sort out local weather change by planting tens of 1000’s of hectares of recent woodlands, surroundings minister Lord Goldsmith has warned.

Gray squirrel up close

The grey squirrel – “a widespread and very quite a few invasive animal” in keeping with broadcaster and naturalist Chris Packham

Grey squirrels have additionally pushed the UK’s native pink squirrel to the verge of extinction throughout a lot of the nation.

There are considered simply 160,000 pink squirrels left within the UK, with solely 15,000 remaining in England.

Grey squirrels are considerably bigger and stronger than reds and carry a squirrel pox virus that’s lethal to reds however to which they’re immune.

The normal method of managing the grey squirrel inhabitants is by culling them. However grey squirrels breed quickly and populations can get well shortly. A century of culling packages has failed to scale back the inhabitants.

Contraceptives for squirrels

Dosing the animals with a contraceptive drug is a extra humane different and can in the end be simpler, says the lead scientist on the challenge, Dr Giovanna Massei, from the federal government’s Animal and Plant Well being Company (APHA).

She says her staff have developed a vaccine that prompts the immune system to limit the manufacturing of intercourse hormones, which leaves each female and male squirrels infertile.

The drug just isn’t everlasting, and additional checks are being carried out to discover a dose that has a long-lasting impact and is secure to make use of within the wild.

The staff have additionally developed a particular feeding hopper with a weighted door designed to maintain out species aside from squirrels.

Trials in Yorkshire and Wales confirmed 70 per cent of squirrels in every wooden visited the bait containers over a 4 day interval – the one different animals that acquired in had been two significantly enterprising mice.

The plan is to bait the hoppers with pots of a hazelnut paste grays discover “irresistible” and which can be laced with the brand new contraceptive.

The scientists are additionally exploring particular feeders for use in areas the place there are each pink and grey squirrels. These can be triggered by a plate which weighs the animals and solely lets the heavier grays get entry to the bait.

picture of a trap

Particular feeding hoppers are being designed to manage the contraceptives

Dr Massei says pc modeling exhibits the contraceptive technique may deliver grey squirrel populations to the brink of extinction in some locations.

“It may even eradicate them from some areas, offered you are able to do a coordinated management over an space, so they do not begin to re-immigrate”, Dr Massei says.

If the work with grey squirrels is profitable Dr Massei believes related strategies could possibly be used to assist management the inhabitants of different invasive mammals together with rats, mice, deer, and wild boar.

The analysis is being funded by the UK Squirrel Accord (UKSA), a partnership of forestry and conservation organisations. It has simply raised over £1m to cowl the analysis and growth of the challenge.

The contraceptive scheme is a crucial further non-lethal instrument for managing grey squirrels, says Kay Haw, the director of the UKSA.

“Purple squirrels now solely survive in island ecosystems the place there are no grey squirrels or the place a pink squirrel group group are working onerous to maintain again the grey squirrels”, she says.

A gray squirrel sitting by a tree in a forest

Contraceptives – a non-lethal method of controlling grey squirrel populations

The monetary value of the harm grey squirrels do is estimated at £37m a yr in England and Wales alone. The associated fee to the UK’s biodiversity has not been calculated.

A mature oak tree can assist as much as 2,000 different species.

The initiative has extensive assist, together with from the Prince of Wales, who was instrumental within the establishing of the UKSA.

The animal rights strain group Folks for the Moral Therapy of Animals says if inhabitants management must be carried out, it backs non-lethal choices.

Nevertheless it cautions: “We mustn’t neglect that grey squirrels and different species deemed “invasive” are the place they’re via no fault of their very own and completely as a consequence of human carelessness, and so they need to be left in peace.”

The broadcaster and naturalist Chris Packham believes a species-specific oral contraceptive could possibly be a “dream ticket” if it proves to be economically viable and sensible.

He describes the challenge as “non-violent direct motion” to manage “a widespread and very quite a few invasive animal” and suggests an effort must also be made to encourage pine martens again into their earlier haunts throughout the nation.

These predatory mammals – a local UK species that has suffered historic persecution – have been proven to reverse the unfold of invasive grey squirrels in Scotland and Northern Eire.

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