Poet and revolutionary Pádraig Pearse once wrote about Ireland’s red squirrels,

Sometimes my heart hath shaken with great joy,

To see a leaping squirrel in a tree.

One hundred years after the sight of playful red squirrels gave such pleasure to Ireland’s most famed rebel bard that same spectacle could soon vanish for good.

At the moment there are two types of squirrels found in Ireland: the native red and the larger, more aggressive North American grey. The latter is an invasive species and was first introduced to Ireland in 1911. Six pairs were released in County Longford and they have gradually spread to 26 of Ireland’s 32 counties.

Long considered vermin, grey squirrels destroy native woodland, stripping young saplings of their bark, dig up flowers and raid birds nests.

As long ago as 1931 their presence across the Irish Sea in Britain led one ecologist to mournfully lament, “I know of more than one patriotic Englishman who has been embittered against the whole American nation on account of the presence of their squirrels in his garden.”

More seriously still, wherever greys are sighted the extinction of the area’s native red squirrel population slowly but surely follows. Whilst the greys don’t kill their red cousins themselves, they do carry the deadly squirrel parapox virus. It doesn’t affect them but if picked up by a red squirrel the infected animal will suffer an excruciating death within two weeks.

They’re also more likely to eat first the green acorns that reds depend on and, even if they’re not ill from the parapox virus, a hungry red will refuse to breed and they’ll soon fade away into the folk memory of their former home.

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There are currently about 140,000 reds across Ireland and Kelly Muldoon from Ulster Wildlife says the population in Northern Ireland could all be gone within a generation.

“Significant progress has been made by local red squirrel groups in halting the decline of red squirrel populations and controlling the spread of grey squirrel populations,” she told IrishCentral.

“But they are not safe yet – constant conservation effort is likely to be needed for as long as grey squirrels are present nearby.”

And it’s not just in Northern Ireland that the red squirrel finds itself hemmed in and threatened by greys: whilst the number of reds are thought to have increased recently in the midlands, Ireland’s Department of Heritage believes the greys are expanding their range across more southerly counties.

The Red Squirrel Survival Trust drew up a map in 2010 showing where in the UK we red squirrels were in 1945 & in 2010 pic.twitter.com/hLKmfMOO

— Sciurus Vulgaris (@red_squirrels) March 21, 2012

Most believe the reds’ best hope of survival lies in the culling of greys. It’s a practice that horrifies animal rights activists but is considered effective.

In the twilight years of the 20th century the Welsh island of Anglesey had only 40 red squirrels left. Now, after nearly two decades of persistent trapping and shooting or battering to death of the invasive greys by a local squirrel group, the number of reds has shot up to an estimated 700.  

Northern Ireland has eight local squirrel groups, but rolling back the relentless march of the greys requires hours of dedication each week and volunteers are thin on the ground.

One such woman is Pam Hardeman from Eglington in Co Derry. She recalls seeing reds in her garden, “That’s what got me hooked”, and felt the arrival of greys in her area was a call to arms.

Her local squirrel group was set up in 2009 and has concentrated its efforts on nearby Muff Glen Wood; grants followed and they bought feeders, cameras and traps.

Every Sunday a hardcore group of six meets to refill the feeders and check the recordings for greys. If one is spotted on camera then traps are carefully laid and checked daily.

“If there’s a grey in them, we have disposed of them and if there’s red squirrels in we just release them,” Hardeman told IrishCentral.

“It is a lot of work but you do it because you just love the little animals and you want to protect them.”

The disposing used to be done by shooting but the group has recently bought a spring trap that crushes the skull of the doomed squirrel, killing it instantly.

“It’s just literally one bash on the back of the head… it’s so much easier,” Hardeman explains.

Their persistence has paid off and the wood, once home to reds at one end and greys at another, is, for now, safe with only one grey sighted in the past three months.

Most locals are supportive but a minority view their actions with unconcealed disgust and traps have been stolen or destroyed.

Perhaps that’s why, she suspects, Derry City and Strabane Council are reluctant to allow them to expand their trapping into other woods popular with walkers.

Even if they were allowed to expand into new areas eradicating greys from the county would require a lot more volunteers than the group currently have. However much local people would like to see reds survive in Derry, few are willing to give up  time on a weekly basis to help them.

“The main thing is educating people,” Hardeman admits.

“People don’t realize the danger the grey squirrel is to the red squirrel. That’s the problem. You think you’ve got rid of them all and suddenly you’ve got an influx.”

As an alternative to culling UK Squirrel Accord is trying to develop a vaccine that could be used to sterilize greys en masse. The idea is being funded by the British Government and has the backing of the organization’s founder and patron, Prince Charles, but the vaccine is still some years away from being finished.

In the meantime many hope that a revival in the fortunes of another animal will help; the weasel-like pine marten, like the red squirrel, is native to Ireland but during the 20th century it was hunted nearly to extinction. Called in the Irish language cat crainn, which translates as ‘cat of the tree’, for centuries it was coveted for its handsome fur and as such killed for its pelt, shot or poisoned by farmers and clung on only in the most isolated parts of Connacht due the loss of the forests it depended on for survival.

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Protected under law since 1976 in the Republic and since 1985 in the north, the species is undergoing a slow revival and research by scientists from NUI Galway have concluded that nearly everywhere pine martens are found, grey squirrels are not. Out of all the areas surveyed only in Rathdrum, County Wicklow were the two mammals found to be living side by side.

“The negative association between grey squirrels and pine marten was so marked that it was concluded that the distributions of the pine marten and grey squirrel in Ireland are inextricably linked,” the report concluded.

Pine martens, they found from examining the animal's droppings, are highly successful at preying on grey squirrels but don’t seem quite so able when it comes to reds. It’s thought that the reds are harder for the martens to catch: they are smaller and more nimble than their grey cousins and they also spend less of their time foraging for food on the ground.

Another theory behind the greys’ inability live in territory also occupied by martens is that once they realize such a fearsome predator dwells in their midst they stop breeding from the stress or even leave the area entirely.

All of which has lead to speculation from conservationists that the expanding range of the pine martens could lead to the happy demise of the grey squirrel in other parts of Ireland.  

British commentator George Monbiot excitedly predicted that thanks to the martens, “in another 20 years the last of them [the greys] will have been driven into the Irish Sea, and Ireland will have been reclaimed by the reds”.

His optimism is not shared by Dr Emma Sheehy who conducted the study into the links between pine martens and squirrels. She has cautioned against hopes that martens could spread across the whole of Ireland.

“We actually know very little about the true potential of contemporary pine marten numbers in much of Europe, as pine marten populations have been decimated by human impacts historically as a result of hunting, persecution and deforestation,” she wrote following the publication of her research.

Emphatically however martens are not urban creatures, meaning they cannot be relied upon to remove greys from Ireland’s cities – if at this point that is even possible.

Pam Hardeman doubts the habitat of her local area is suitable for pine martens; they’ve been spotted in neighboring Donegal and Fermanagh but no one in her squirrel group has seen one locally.

Instead, she believes the red squirrel’s salvation lies with local groups like hers, without which she believes the greys would have overrun Muff Glen Wood like they have done in countless forests, towns and villages across Ireland.

Can the tide be held back indefinitely?

“I would hope so, yes. As long as there’s people like us here to preserve them I see no reason why not.”

The extinction of an entire species would be nothing new for Ireland. As every child in Ireland learns at school St Patrick drove the country’s snakes into the sea. Fifteen hundred years a similar extinction is happening but this time no one can agree on whether it’ll be the reds or the greys who end up in the sea.