If I were to ask you to name one of our most pressing conservation matters in the 21st century, what would you say? The issue of our persecuted birds of prey? The re-wilding debate? Fox hunting? Badger culling and TB? Or maybe even the continuing battle between the grey and red squirrel? They are all huge issues that we are yet to properly address in the UK, but we can probably all agree that there is one battle that has been raging in our forests for years. The endless struggle for dominance between the red and the grey squirrel.
As we all know, the red is our native species, it has it’s very roots here and therefore, we want them to prevail in this war. Although an issue that we are all so familiar with, as with many wars, we often find ourselves asking, ‘where did it all begin?’ Quite right too, for to understand something, we need to know all the facts (or as many available), and knowing the very origin of an issue helps to explain the problem itself. Once again I hear you saying ‘get to the point Ellie’, so I won’t delay any further. So, my point is, where did the grey squirrel actually come from? Now, before you ridicule me too much, with cries of ‘we all know it’s from North America!’ let me explain. Yes, the grey squirrel is indeed from America, but how did he come to arrive on our shores? The answer? Those helpful Victorians.
That’s right. They brought us the rhododendron, they introduced the Japanese knotweed and they can add the grey squirrel to their rather impressive list, for if it weren’t for the Victorians, we may not have such a problem with the grey squirrel. So, the Victorians are at fault, but there were a lot of Victorians, we can’t make every single person who lived in this period responsible. Is it possible to narrow the blame down at all? Surely not! Or surely? Showcasing a few investigative skills reminiscent of Sherlock Holmes, Imperial College may have answered our question, though this time the study is not in pink, but a study in red and grey . In fact, they have named one of our chief suspects. May I introduce, the 11th Duke of Bedford, Herbrand Russell. Take a deep breath, because we are about to accuse the Duke of a heinous crime. The crime of ‘squirrel spreading’!
Although an enthusiastic conservationist, the Duke of Bedford played a significant part in one of the most disastrous non-native species introductions that the UK has ever known. Importing 10 grey squirrels from North America, he then released them into the grounds of his own home in Woburn Abbey, Bedfordshire, as well as presenting them as gifts to his friends as unique additions to their estates. Unaware of the damage they would cause, he then released even more into Regents Park, London. Over the years, grey squirrels have earned a kind of mythical status in the UK. They are portrayed as super invaders that cannot be stopped at any price, and we award them a kind of War of the Worlds invasion status. However, the recent study by Imperial College states that this is far from the truth and that it is us humans who are to blame for their spread (surely not!).
However, Herbrand Russell, president of the Zoological Society of London, was not all bad. Indeed, he is thought to be responsible for the rescue of the Milu deer from extinction through a successful breeding program at his own home. But with the introduction of the grey squirrel all those years ago, what exactly is the is the situation now? We all know the red squirrel is in trouble, but how much trouble? Well, from just a few greys, came 2,520,000, whilst our reds now sit at around 10,000-15,000. That’s means greys outweigh reds by approximately 168 to 1. So, did they all come from just the odd few, whilst us humans stood at the sidelines, powerless to stop it? Not quite. In fact, DNA analysis shows that several local populations were introduced entirely by humans, with individual groups showing little genetic similarity. Previously, it was believed that the invasion of the greys came in one great charging front, with just one mistake from us leading to a total invasion. Now however, it seems that several mistakes from us meant that a number of groups of greys invaded from several corners of the country.
Dr Signorile, who carried out the research said:
“It has been thought since the 1930s that grey squirrels were all the same, spreading across the country as one invasion front. After a century, genetics has proved that this isn’t correct. They are not that good at breeding and mixing – in fact there are clear signs of inbreeding.”
From a large DNA database, containing the genomes of 1500 grey squirrels in the UK and Italy, Dr Lisa Signorile found that in most cases, new grey squirrel populations were not genetically related to other populations that lived near them. Therefore, the only way these animals could have spread so far without breeding, is through human intervention. This is shown in a particular example with the grey squirrels of Aberdeen showing a closer relation to those all the way down in Hampshire! That’s around 550 miles away and there are of course, other grey squirrel populations along the way. So, however unaware we may be, we are still helping these animals to travel around and invade the territory of the red. The study also found that one grey that had been captured on the Isle of Skye in 2010, actually game from Glasgow. The genetic profiling used to confirm this, supported the theory that this self styled Indiana Jones grey squirrel could have sheltered in a car bonnet and then escaped onto the island.
Now, a lot of money goes into the conservation of the red squirrel, but this study suggests that we are still not tackling the problem properly. Dr Signorile has claimed that more work needs to go into preventing their spread, rather than just controlling their numbers. Although the general opinion is that squirrels find their own ways to invade, humans may be more instrumental than we realise. In Scotland, one of the last areas to be invaded by the grey, this is even more important. There are still areas where the grey has not established and we need to make sure it stays that way. Although the grey squirrel has become a familiar sight and many enjoy seeing the grey as a regular visitor to their garden, the impact they are having on the red is a huge conservation problem. But perhaps it sounds like all too much of a big ask? How can we possibly control the spread of a species if we’re not even aware we’re doing it! Well, it’s what I like to call a challenge! At least with this information we can attempt to stop the spread of the grey to those areas which do not yet have them.
Currently we are predominantly a red and grey country when it comes to squirrels (with a few blacks), we should try everything we can to keep the reds in the running.
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