Back in November I wrote a piece for Walkhighlands about pine martens, in which I referred to a study that was underway at the time into their intriguing relationship with both red and grey squirrels. The results of that study were published last week and made headline news, so now seems a good time to revisit the subject. Many of you are doubtless familiar with our squirrels but I think it’s still worth going back to the very beginning of this fascinating story.
The red squirrel
The red squirrel is the only squirrel native to the British Isles, i.e. it wasn’t brought here by us, rather it moved here naturally of its own accord after the last ice age receded around 10,000 years ago. It likely had millennia of stable existence until humans began cutting down its forests, a process that came to a tipping point in the 18th Century when it led to local extinctions of red squirrels across the Highlands. The population was topped up using donor populations from England and Scandinavia, which would have been pointless had it not coincided with a phase of reforestation across Scotland in the 19th Century.
Populations subsequently recovered to the extent that the red squirrel was regarded as a pest, stripping bark from trees in order to get at the sap beneath, and by the start of the 20th Century there was a bounty on those red tails. The Highland Squirrel Club was formed in 1903, which sounds like an adorably twee and fluffy weekend nature group but was really more of a killing spree. Between 1903 and 1946, 102,900 red squirrels were killed, and their tails presented in exchange for the bounty.
The grey squirrel
Larger and bulkier than reds, and without the distinctive ear tufts that the red wears in the colder months, grey squirrels are from the eastern half of North America. They were brought here as an ornamental species in the late 19th Century to add exoticism and entertainment to private estates in places like Cheshire, Bedfordshire and Strathclyde. Fertile, free-roaming squirrels weren’t going to be contained within gardens of course, and so they liberated themselves and set about colonising adjacent areas. Arguably the red squirrel was already absent from many of those areas on account of habitat loss or persecution, but in the kinds of habitat that dominated in much of England, i.e. woodlands with a high proportion of broadleaf trees like beech and oak, the grey squirrels out-competed any remaining red squirrels for resources.
Greys can eat bountiful tannin-rich food sources like acorns when they are green, whereas reds can’t digest them until later in the season when they’re ripe, by which time they’ve probably already been snaffled. Greys also find it easier to put on weight for the winter, and for reasons that aren’t entirely understood they have an adverse impact upon the breeding success of female red squirrels that occupy the same woodland.
Greys also act as a host for a disease called Squirrelpox Virus (SQPV), to which the greys are immune but which usually kills red squirrels in a matter of weeks. For all these reasons and more, the red’s range shrunk quickly in the 20th Century, and in most cases this went alongside a similarly rapid expansion in grey territory. Today the respective populations now number around 120,000 reds to perhaps 2.5 million greys, with reds outnumbered by about 20 to 1.
The UK squirrel map
Not long ago my dad mentioned to me in passing how he remembers sitting in class at his school in Croydon, South London, and seeing red squirrels in the school grounds. I was genuinely surprised because although I knew red squirrels were now extinct across much of the UK, I hadn’t realised how recently and rapidly they had declined. Today, notable populations only remain in Northern England, Merseyside and the islands of Anglesey, Brownsea and the Scillies, plus some fairly healthy strongholds in Northern Ireland.
In Scotland, which is home to three quarters of the UK population, red squirrels are still found across much of the country with the exception of the Central Belt and most of the land and islands west of the Great Glen. Arran is a notable exception, being a red stronghold free from greys. Grey distribution across the UK is easier to summarise. Just draw a line between Loch Lomond in the west and Montrose in the east, and pretty much everywhere south of that has them, plus an isolated population in and around Aberdeen.
Turning of the tide
Details as to how public opinion turned around in favour of the red squirrel are sketchy, but Beatrix Potter’s introduction of Squirrel Nutkin in 1903 is widely cited as a turning point. It fostered red nostalgia among what was presumably a mostly urban readership in the subsequent decades, not least in those parts of the country where reds had already become scarce or had completely disappeared. But there was certainly also a growing awareness in the early 20th Century that greys were ‘taking over’.
A children’s book called ‘A squirrel called Rufus’ was doing the rounds in the mid 20th Century, in which a band of reds defended their country from an alien invader, the grey. And the book was explicitly framed in those terms, as a war with a battlefield. Release of greys into the countryside had continued right up until the 1920s, but by the 1930s folk were noticing the squirrel swap going on in their parks and gardens, and in 1932 it was made illegal to hold a grey squirrel in captivity.
The tide was turning but it would be another 50 years before the red squirrel would be afforded full legal protection along with the rest of the UK’s wildlife, via 1981’s Wildlife and Countryside Act. That same legislation listed the grey squirrel as an invasive species, which meant it was now illegal to release one into the wild or to even allow it to escape after capture.
Red conservation
Trials have begun on an oral contraceptive for grey squirrels, and research is underway into a vaccine to protect red squirrels against Squirrelpox, but both are a long way off from being viable and neither are likely to be sufficient in themselves. Efforts have therefore focused on a package of measures including long-term monitoring, habitat management, and the lethal control of grey squirrels in and around areas where reds are still found.
In Scotland the conservation work is being driven by the Saving Scotland’s Red Squirrels partnership, which finds itself policing the frontier of the grey squirrel’s northerly advance. Control measures north of the Loch Lomond/Montrose line (and around Aberdeen) involve trapping and killing grey squirrels, while to the south of the Central Belt the focus is on establishing Priority Areas for Red Squirrel Conservation (PARCS) in places where red squirrels have the best chances of survival.
There are then 19 ‘strongholds’ across the Highlands, Arran and Southern Scotland, mainly on Forestry Commission land and mostly consisting of mixed forests of spruce, pine, larch and fir in which reds have a competitive advantage over greys, and where large-seeded broadleaf species that give grey squirrels an advantage, such as beech and oak, are discouraged.
Another conservation technique is translocation, i.e. taking red squirrels from a healthy donor population and releasing them somewhere else to bolster existing populations or establish entirely new ones. The charity Trees for Life is currently doing this for ten sites in the Northwest Highlands, whose suitable forests would likely have been naturally re-colonised by red squirrels were it not for the fact that the old pine forests are now fragmented, leaving them geographically isolated from the nearest viable red squirrel populations.
In the Central Belt the focus is on containing any Squirrelpox outbreak as and when it arrives, which mercifully it has yet to do. The understandable approach there is that with red squirrels mostly absent and grey squirrels now ubiquitous, resources are best focused elsewhere. As a Fifer, that can be a hard pill to swallow because we do still have red squirrels in the county, but we don’t feature in the annual Saving Scotland’s Red Squirrels reports. I understand why, but sometimes it feels as though our struggling reds have been sacrificed. Still, the overall approach in Scotland has been successful so far and the 2017 survey results show red squirrel populations here are mostly stable, and even increasing in the former grey stronghold of Aberdeen.
Oh but it’s complicated
Red squirrel protection efforts have undoubtedly gone hand in hand with the ‘fluffification’ of conservation, whereby adorable animals have become emblems of organisations or their campaigns. But at the same time the grey squirrel has been demonised, which is something I don’t personally agree with, so when I go into schools to teach kids about red squirrel conservation I always stress that grey squirrels aren’t inherently bad. They’re just doing what comes naturally. Yes, I do what I can for red squirrel conservation but that doesn’t mean I can’t enjoy watching grey squirrels as much as any other wild animal. Indeed, where I grew up the grey squirrel was all I’d ever known.
They’re entertaining, charismatic, sentient creatures so I can well understand why the grey cull is resisted on a moral standpoint, and a recent petition appealing to the Wildlife Trusts to abandon lethal methods of control attracted nearly 130,000 signatures. Others question whether red conservation is even worth the effort. Conservation biologist James Borrell wrote an interesting piece in the Guardian a few years ago called ‘If you really love wildlife, forget about red squirrels’, in which he said:
‘In an ideal world, maintaining our native squirrel would be a justifiably worthwhile thing to do. But in the face of global biodiversity loss, does the colour of our squirrels really matter?”
The red squirrel might be losing ground in the UK but it’s doing okay across the rest of its massive Eurasian range. The International Union for Conservation of Nature (IUCN) rates it as a species of ‘least concern’, whereas there are thousands of other species in greater need: 32,007 out of 91,523 species assessed for the 2017 Red List are classified as ‘near threatened’ or worse, including 5,583 that are ‘critically endangered’. Should we direct our squirrel money to more deserving species? Would our £millions have pulled the northern white rhino back from the brink? Or the Pyrenean Ibex? What of the thousands of non-fluffy, un-huggable creatures of this world that are teetering over the abyss?
Abandoning fluffy native wildlife to its fate is an uncomfortable thing to ponder. What would happen if we did so with the red squirrel? Certainly the two squirrels can exist alongside one another and indeed there are places where they have done so for decades. But those tend to be where habitats are diverse and where each species exploits a specific niche within them. There’s a chance that red squirrels could acquire immunity to Squirrelpox over time but it’s hard for them to recover in areas where their population has been decimated and since been replaced by greys. Hmm, if only there was a natural way of somehow tipping the balance in the red squirrel’s favour….
Pine marten to the rescue?
For all our self-centred, historical disregard for predators and our naïve experiments with moving animals around the globe it’s a miracle we still have pine martens in the UK, but as they slowly recover they are becoming the unwitting hope of red squirrel conservation. You can read about Sheehy & Lawton’s original Irish study of pine martens and its implications for Scottish red squirrel conservation in my previous article, but the headline news is that a similar study undertaken here decisively corroborates the Irish findings. That being, that where pine martens are well established there are significantly fewer grey squirrels. Moreover, the number of red squirrels actually increases despite both squirrels being prey for the pine marten.
The theory is that because grey squirrels are heavier, slower and spend more time on the ground than red squirrels, they are easy pickings for a creature that they are historically unfamiliar with. The lighter, more arboreal reds on the other hand have lived alongside pine martens for thousands of years and are more savvy.
Modelling based on the Scottish data predicts almost zero grey squirrels where pine marten density is high and well-established, but the study is quick to acknowledge the dataset can’t forecast whether pine marten resurgence will lead to the total eradication of grey squirrels in Scotland. Never the less, they are confident enough in their findings to say that, if nothing else, the resurgent pine marten will ‘likely profoundly alter’ the chances of the two squirrel species due to its impact on the presence/transmission of the squirrelpox virus.
Job done, then?
Erm… no. Martens aren’t prolific breeders, they are still persecuted, and just like the red squirrel they themselves favour habitats that simply don’t exist in much of Scotland, and which are even more scarce down south. School kids in Croydon certainly won’t be seeing red squirrels (or pine martens) any time soon, but where there is suitable habitat for both the red squirrel and the pine marten there is certainly cause for optimism in much of Scotland. Greys are surely here to stay though, in which case active red squirrel conservation will likely continue indefinitely, as will the debates about how we go about it and, somewhat uncomfortably, whether we should even bother.