University Observer elsewhere on the interwebs

FacebookTwitterRSSYoutube

A tale of two squirrels

A deadly virus has reached our shores and is set to devastate our already ailing red squirrel population. Alison Lee writes about the dangers posed and the efforts being made to save the creatures.

Cast your mind back to your primary school days and you will probably remember learning about Ireland’s wildlife. You might even remember the term ‘Iora rua’, or ‘red squirrel’. This shy tree-dwelling mammal can still be found in forests across the country, but this may not be the situation for much longer.

Since the introduction of the grey squirrel to Longford in 1911, red squirrels have grown scarcer and their distribution has shrunk dramatically; so much so that the National Parks and Wildlife Service has had to take measures to protect it. Ireland isn’t the only country where this animal is in danger; the red squirrel has become extinct in England and Wales due to the introduction of the grey squirrel in 1876. However, another factor helped along the disappearance of red squirrels in the UK: the lethal squirrel pox virus (SQPV). It was long believed that Ireland was free of this disease – that is, until now.

This January, the first Irish case of SQPV was confirmed by Prof. Sean Callanan of the UCD Veterinary Pathology Department. The squirrel was found by local resident Kevin Phelan while walking in woods in Hollywood, County Wicklow and since then two more cases of the disease have been confirmed. This development could spell doom for our native squirrels.

It is widely believed that grey squirrels fight with and kill their red counterparts, but this is not the case. They are simply bigger, breed faster, have more young per litter, and can exist at higher population densities – therefore they have displaced the red squirrel population by competition. Reds are now mostly found in inhospitable pine forests where food is too scarce for greys to thrive.

Grey squirrels are simply more adaptive – they are happy to live near humans and although they’re cute and playful, they can be extremely destructive to homes and gardens. This has resulted in them being classed as a household pest alongside rats, wasps etc. They also strip bark off trees and significantly impact upon commercial broadleaf timber production.

Grey squirrels have another means of thinning out the red squirrel population; it is believed they are carriers of the squirrel pox virus, but have evolved an immunity and thus are resistant to its potentially deadly effects. It is yet unknown how they transmit the disease to red squirrels, but scientists believe it may be passed on via secretions from scent glands that they use to mark their territories. Its effects on non-immune squirrel species are devastating.

The virus causes lesions similar to those seen in rabbits with myxomatosis – swellings, ulcers and scabs develop around the animals’ eyes, mouth, nose and paws and it is believed the squirrels simply die of dehydration, respiratory problems and starvation as they cannot forage for food or eat. The virus does not seem to affect their internal organs.

Yet there may still be hope for the red squirrel – in 2008, a UK scientist discovered a handful of animals that had developed antibodies to the disease, thus indicating that some red squirrels have the potential to become immune. When myxomatosis was introduced to the UK in the 1950s, the death rate amongst rabbits was almost one hundred per cent, but those with a natural immunity survived, bred and now the death rate has decreased to thirty-five per cent. A similar situation may occur if enough red squirrels develop an immunity to the disease and live long enough to produce immune young. The development of an SQPV vaccine could also theoretically save the red squirrel. In fact, a Scotland-based charity called Wildlife Ark Trust are currently trying to do just that, but it will take at least another year to develop an effective vaccine, and subsequently three years of trials will be required before it can be used in the wild.

So what lies ahead for our red squirrels? If the virus spreads throughout the country it is likely that they will go the same way as their counterparts in England and Wales. Although the loss of a native species would indeed be tragic, Darwin’s principle of “survival of the fittest” doesn’t take pity or make exceptions for any animals, no matter how cute or charismatic they may be.

Since humans set this tragedy in motion by introducing grey squirrels to Ireland, it is only right that we at least make an attempt to preserve one of the few Irish mammals that still survive in the wild. This will require measures such as supplementary feeding, monitoring and recording squirrel numbers, careful forest management and the humane culling of grey squirrels. Yet these measures require money and resources that Ireland is currently lacking. Therefore the future may be bleak for Iora Rua – only time will tell.

7 Responses to A tale of two squirrels

  1. Angus Macmillan

    February 1, 2012 at 11:04 pm

    Victimising Grey Squirrels
    Version 2. December 2009

    1. Native Species?

    A key criterion set by the conservation industry for determining if a species is “native” is that it should have evolved with all other species within its own ecosystem and not have been introduced or assisted by man to arrive at what is regarded as its natural location. In short, it should have got to where it is by its own efforts and evolved naturally. If man assisted it, it is regarded as “non-native”.

    This is confirmed in Scottish Natural Heritage’s website:

    “3.5. Native species are presumed to be those that are present in Great Britain by natural means. In general they migrated (or were transported by other species) into Great Britain after the last Ice Age, without the assistance of humans.”

    “3.6. Non-native species have been introduced to Great Britain, either deliberately or accidentally, by humans.

    However, this criterion is profoundly flawed and is only credible if the actions of humans are wrongly regarded as outside of nature.

    There is no doubt that in the animal world we are pretty smart cookies. We have evolved to manufacture modes of air, sea and land transport, store extensions of our memories on computers, provide ourselves with heat and light, cut ourselves open to remove diseased tissue, grow our own animal and vegetable food, and destroy other members of our own species with unimaginable ferocity if they dare to compete with us for desirable objectives. But none of this excludes us from nature. It only shows we have the mental and physical capacity to use tools and weapons made from natural resources to a greater degree than any other species on the planet. So as we are part of nature, it follows that if we transport fauna or flora to our homeland because we find them attractive, then the claim that these introductions are only acceptable “if transported by other species” is exposed as anthropocentric prejudice, masquerading as science, which serves to undermine the whole concept of native and non-native species.

    In fact, the survival of all species depends almost solely on their attractiveness to other members of their own species, and in many cases their attraction to other species as well. It is ironic that that attractiveness, which is leading conservationists to “protect” the red squirrel, was the reason for introducing grey squirrels in the past.

    Conversely, it is equally ironic that both red and grey squirrels have been demonised as “tree rats” at different times, which has led to tens of thousands being slaughtered because they were intensely disliked for similar reasons. 80,000 red squirrels were killed in Scotland early in the last century by those with forestry interests who blamed them for tree damage.

    Also, if it is important to conservationists that a species evolves naturally over millennia in Britain to earn its “native species” status, then it should be equally important that the same species evolving in a different natural environment abroad should not be regarded as “native” to this country. They can’t have it both ways! But they try.

    It is well known that the grey squirrel was brought from America to England in the late 19th Century but less known that ancestors of the current population of red squirrels in the UK have been largely introduced from various parts of Europe. These animals evolved within a wide range of climatic and environmental conditions and associated with different flora and fauna encountered across the part of the range they inhabited, so for conservationists to argue that these influences are not important is to argue against their own concept of “native species”.

    Both current populations of squirrels, red and grey, have been introduced to this country and there is no evidence that even the earlier red squirrels evolved here continuously from the time of the land bridge to Europe around 10,000 years ago. Scant archaeological snapshots give no indication of a continued presence. Indeed, prior to the 15th century there seems to be no record of the continuous existence of red squirrel populations living in Britain.

    “There is no longer a ‘native’ red squirrel due to the frequent introductions from Europe and habitat defragmentation which has allowed gene flow between previously sub-divided populations.” (Harris et al, 2007)

    2. Habitat and diet

    A common assertion is “when greys move in, reds move out” but the blame should not be laid at the door of grey squirrels, but at the conservationists themselves. If conservationists want to assist the red squirrels to survive, they should be improving their habitat by planting suitable conifer trees in which they thrive, instead of the political and identity-crisis fad of wallpapering the countryside with native broadleaves that favours the greys’ expansion and the reds’ demise. The requirement to plant trees that favour the red squirrel as a barrier to the greys’ expansion is well known to the Forestry Commission.

    Red and grey squirrels have a significantly different diet. A study published in the Mammal Review showed that while both species fed mostly on seeds and fruit’ they could adapt to an abundance of other foods at times of seasonal shortages. In particular the red squirrel was found to largely consume fungi and conifer buds when seeds and fruit were scarce. Greys, on the other hand, will eat acorns – which reds find difficult to digest – and a host of other foods, as widely ranging from deciduous shoots to roots and perhaps the occasional discarded fast food take-a-way that comes their way. Neither species is a serial predator of birds’ eggs or chicks but they won’t pass up an opportunity if it presents itself.

    3. Tree Damage

    “Damage to trees can be beneficial (Forestry Commission, 2006), as wounding can provide habitat for saproxylic fungi and invertebrates, which in turn provide food for woodland birds. Trees killed by squirrel damage can also provide valuable nesting sites for a range of species.” (Harris et al 2007)

    4. Squirrel-pox Virus (SQPV)

    Conservationists tell us that grey squirrels are the “cause” of the red squirrel decline through the transmission of squirrel-pox virus (SQPV) but there is no evidence to support this. It is merely speculation presented as fact. There are a number of ongoing grant funded studies to try to determine the route of infection but would this expensive research be required if the route was already known?

    It is known that the disease characteristics are similar to other poxvirus infections and that most are resistant to drying. This can allow infected lesions or crusts to remain infected for a long time thus allowing the spread of the disease throughout the forest environment by almost any creature that comes into contact with it. Indeed, Scottish Natural Heritage admit they do not know the route of transmission and that “possibilities include being passed by ectoparasites, fleas, lice, ticks and mites which may transfer from animal to animal in the dreys”. They also acknowledge the virus may be airborne spread. Research by McInnes et al in 2006 acknowledges “the possibility that the virus is endemic to the UK and that other rodent species inhabiting the same woodland environment could be harbouring the virus.

    Under a Freedom of Information request “The Forestry Commission have admitted that no routine testing of live red squirrels is undertaken” and they “are not aware of any scientific evidence one way or another as to whether or not there is a resistant population of reds out there”. So it is quite wrong to claim red squirrels have no immunity to the disease. Indeed, recent research by London zoologists has established that red squirrels are beginning to show signs of natural immunity.

    Early in the last century, out of forty-four districts in England where red squirrels had the disease only four districts had grey squirrels present. This suggests that SQPV has been within the red squirrel population for around a century at least and that grey squirrels are victims of a campaign of unfair vilification. Some people even have the audacity to claim that SQPV somehow arrived around the time it was discovered in 1983 but that is about as ridiculous as claiming America didn’t exist before it was “discovered” by Leif Ericson – centuries before Christopher Columbus was born.

    5. Immunocontraception

    Immunocontraception was deemed immoral in the 1930s in mainland Europe, when it was proposed against sectors of the human population. It is equally immoral to use it against wildlife, as it could affect non-target species and introduce a significant risk of unintended consequences. Unscrupulous conservationists could also use it as a weapon of mass destruction of any species in an attempt to control nature. How long before this dangerous technology, if perfected, could be used against the human population? It is not a route that should be considered by any right thinking people.

    6. Culling of Grey Squirrels

    Culling doesn’t work except in closed environments such as islands. According to research it would cost £200,000 per annum to control grey squirrels in Northumberland’s Redesdale Forest alone. – Rushton et al (2002) – and would require to be repeated endlessly as greys will quickly re-colonised voids, sometimes within a few weeks. Culling greys across Scotland will be an expensive and futile exercise. It is well known that culling can lead to an increase in population as those left alive enjoy a better habitat and produce more young.

    “Squirrel culling is not a new phenomenon. Some 60 years ago the Ministry of Agriculture started to encourage people to kill squirrels, offering—I remember it only too clearly—a shilling a tail. I became a very wealthy young man at that time, as we had a lot of grey squirrels in the area and I did not need a lot of encouragement to do something about them. When the government at that time had paid out some £250,000, they decided that that was enough. There was no perceivable difference to the squirrel population.” Lord Plumb, March 2006

    In Merseyside, a buffer zone has been in place for a number of years where grey squirrels are routinely killed. However, increased human exploitation of red squirrels for tourism and the frequent intrusion by conservationists for monitoring population levels was always likely to lead to stress and loss of condition of the red squirrel resulting in an increased susceptibility to disease. The announcement that the red squirrel population had declined by 90% in the past two years was hardly surprising.

    In short, fewer grey squirrels with more conservation and tourist intrusion have resulted in a massive decline in the red squirrel population – definitely not the predicted outcome.

    Recently, The Lancashire Wildlife Trust has claimed productive breeding of red squirrels in Merseyside over the summer has seen numbers rise from between 100 to 200 in October 2008 to between 200 to 400 in October 2009. However, alert readers will note the margin for error has doubled in real terms and for that statement to be true only two additional red squirrels would require to have been born – from 199 to 201. Indeed, a method of counting reds is to record sightings, which could be the same squirrel seen multiple times by different people, and then multiply the result by 7. This hardly inspires confidence in accuracy!

    In a Radio 4 “Living World” broadcast, a Cumbria Wildlife Trust officer failed to find a single red squirrel for the presenter in Thirlmere woodland where there is reputed to be a population of “at least 200”. If they can’t find one for the BBC, how do they know there are 200? This is where a Red Squirrel Trail tour, with no guarantee of seeing a red squirrel, costs a member of the public “twenty quid”.

    Evidential claims made by conservationists are frequently littered with slippery qualifiers that include words like “presumed to be”, “thought to be”, “possibly”, “perhaps”, “may be”, etc. and used as escape routes from being held to account. The careful reader is well advised to look out for these qualifiers before coming to any conclusion as to the merit of any particular claim.

    7. Humane dispatch or brutality

    Grey squirrels usually mate from December to February and again in March to May, although Forest Research has established that they mate all year round. Gestation takes up to 44 days and the young are usually weaned short of three months. This means that most kittens will be dependent on lactating females from mid January to mid-October. Trapping and killing these females at this time results in the extreme cruelty of sentencing their kittens to a lingering death from starvation. There is nothing “humane” about that! It is an act of extreme cruelty.

    What is “humane” anyway? “Humane” and “humane as possible” are words frequently used by conservationists to describe the killing of wildlife. So what exactly do these words mean or are they merely euphemistic references to brutality?

    Red squirrel groups are currently engaged in what they call the “humane dispatch” of grey squirrels by clubbing them over the head with a blunt instrument. However, Scottish Natural Heritage’s area manager for Shetland rightly condemned the brutal killing of twenty-one grey seal pups by a local fisherman, who clubbed them over the head with a blunt instrument. He said, “This is a shocking case. The degree of casual cruelty shows that there is still a great deal of ignorance and prejudice about grey seals”. But let us not forget that SNH, together with the Scottish Wildlife Trust and others are currently engaged in the “humane dispatch” of grey squirrels by the same method, which amounts to gross hypocrisy and double standards.

    Clubbing a grey squirrel over the head is an act of violence and is being promoted and perpetrated nation-wide by government and red squirrel groups. Scientific evidence shows that those who have little regard for the welfare of animals are likely to have a similar attitude to their fellow human beings. Abuse breeds abuse, and in our ever-increasing violent society, what example is it to younger generations that violence and killing is an acceptable solution to a perceived problem of not being native to this country?

    Putting aside the argument of whether the animal is a “protected” grey seal or a grey squirrel, it is logical to say that if the method of dispatch is similar, there is no excuse for describing it differently.

    All sentient animals feel pain irrespective of whether they are “protected” or otherwise.

    8. One small step from racism

    In reality, rather than in the arbitrary and profoundly prejudiced world of “conservation”, all squirrels born in this country are as “native” by birth as we are, irrespective of their colour, background or success. To expect tolerance within our own population but condemn these animals to death on the basis of their ancestral background is extremely hypocritical and only one small step removed from racism.

    It should be appreciated that squirrels, of any colour, are not “ours”. They are independent parallel mammalian populations that inhabit this planet the same as we do and should be afforded the same respect and consideration to live out their lives that we expect for ourselves.

    The Grey Squirrel
    Native by birth – Condemned by origin

    Please read the website
    http://www.grey-squirrel.org.uk

    December 2009 ©

  2. Angus Macmillan

    February 1, 2012 at 11:09 pm

    Perhaps not so native after all!

    The almost daily venomous attack by conservationists on grey squirrels for not being native to this country is dutifully followed up by the claim that red squirrels are “native” to Scotland. However, this may not be so in terms of the conservationists’ criterion for a native species, which is that they are presumed to be those that are present in Great Britain by natural means. In general they migrated (or were transported by other species) into Great Britain after the last Ice Age, without the assistance of humans.

    There certainly is some pretty shaky evidential snapshots of them existing in England but never in Scotland. It is understood that some of the caves in the Wye Valley were subjected to flooding following the retreat of the last ice age when the North Sea met the Atlantic. It could be feasible that the remains of bones and significantly, marine molluscs, found there and at the Undercliffe in the Isle of Wight might be no more than debris washed in from continental Europe during that period of immense upheaval

    For some time I have been looking into the use of squirrel fur during the early medieval period and can find no record of indigenous squirrel fur being used in Great Britain. In the later middle-ages the central distribution point for squirrel skins from the Baltics, Scandinavia and Russia was Bruges, from where skins were imported to Great Britain via London and the Eastern Ports including York which was at that time navigable from the North Sea. Therefore, it is no surprise that the first mention of “squirrels” in England was by Hugh, the Bishop of Lincoln, (later St Hugh) towards the end of the 12th century. So a far more likely explanation for the arrival of the red squirrel in the British Isles – rather than being regarded as “native” on the strength of bone finds that appear not to have belonged to the same sub- species – is that they were imported as live animals from mainland Europe because of the well known and recorded price fluctuations of European skins that threatened the livelihood of skinners and tanners throughout Great Britain. This would explain the thousands of years of no squirrel records in England and red squirrels establishing themselves in the later middle-ages, probably in similar circumstances to that of the American mink nowadays. It is also understood that red squirrels were kept in captivity in Ireland for their fur, which was exported to mainland Britain.

    Rather than the red squirrel being a “native species” there is a much better case for regarding it as being introduced on a commercial basis by fur industry entrepreneurs as a “grow-our-own-fur” enterprise that failed because the thicker fur from colder parts of Europe and Russia was more desirable by the end user. These furs were known as, greywerk, miniver, gris, and vair – all continental names.

    When I recently asked Scottish Natural Heritage what evidence they had that the red squirrel was native to Scotland, they replied, “We note, but do not agree with your contention that red squirrels are not native”. Obviously they have no evidence; only a belief.

    Perhaps they also believe in fairies.

    I have heard people in Ireland do :-)

  3. Al

    February 4, 2012 at 12:48 am

    Angus Macmillan
    Could you please publish some sources for the claims you make? Rather than just re-posting verbatim an essay. I can get the same thing by putting ‘grey squirrel’ into Google. There is such rancour in your post.

  4. Angus Macmillan

    February 6, 2012 at 9:08 am

    Al said, “Could you please publish some sources for the claims you make?”

    Like what? I have in numerous cases. Please be specific.

    Would you like to reciprocate by giving sources that show red squirrels are “native” – not just blind beliefs.

  5. Al

    February 9, 2012 at 9:34 pm

    Like a peer reviewed scientific publication on the subject. Not a reference to a Radio 4 Documentary.
    I can reciprocate in kind but you came out guns blazing. The burden of proof is on you

  6. Angus Macmillan

    February 10, 2012 at 11:43 pm

    Al. Is that the best you can do? You want a peer reviewed scientific publication of a Cumbria Wildlife Trust officer failing to find a single red squirrel for the Radio 4 presenter in Thirlmere woodland where there is reputed to be a population of “at least 200? I doubt if one exists. If you think I’m not telling the truth why not contact Radio 4. The recording will be the proof.

    So what evidence do you have that the red squirrel as a species is “native” to Ireland? If you think it is the burden of proof is on you.

    You seem to take undue offence at my postings. Why is that?

  7. Angus Macmillan

    February 11, 2012 at 8:46 pm

    Just an interesting thought.

    If as is stated in the article above the first grey squirrels were introduced to Ireland in 1911 and they are carriers of SQPV, why has it taken all this time for the first red to become infected with the disease?

    Anyone know?