Let Nature Do Its Own Work

The Pine Marten, once common in the UK, is a natural predator of the grey squirrel and has successfully reduced their numbers in Ireland. Photograph: Alamy

The Pine Marten, once common in the UK, is a natural predator of the grey squirrel and has successfully reduced their numbers in Ireland. Photograph: Alamy

Not every problem in the natural world has a solution, let alone a simple one; and there is always that law of unintended consequences, but we like the way this proposal sounds as an alternative to other forms of eradication:

Is there anything more stupid than the government’s plan to kill grey squirrels?

I ask not because I believe – as Animal Aid does – that grey squirrels are harmless. Far from it: they have eliminated red squirrels from most of Britain since their introduction by Victorian landowners, and are now doing the same thing in parts of the continent. By destroying young trees, they also make the establishment of new woodland almost impossible in many places. As someone who believes there should be many more trees in this country, I see that as a problem. A big one.

No, I oppose the cull for two reasons. The first is that it’s a total waste of time and money. Here’s what scientists who have studied such programmes have to say:

“To date, there has been no successful method developed in the long-term control (nor indeed the eradication) of grey squirrel populations … a recovery in numbers was found to take place within 10 weeks of intensive culling programs.”

You pour the money in and it pours out the other side. The government’s plan to sponsor an “eradication programme” to the tune of £100 per hectare per year is futile; though it will have the effect of transferring even more public money to rural landowners.

I doubt you’ll be surprised to hear that the idea was approved by the former environment secretary Owen Paterson, whose primary mission in office appears to have been showering his chums with gold, while ruthlessly cutting any spending that might have delivered wider benefits. This was the man, remember, who almost doubled the subsidy for grouse moors.

My second reason for opposing the cull is that there is another way of dealing with grey squirrels, which requires hardly any expense, indeed hardly any human intervention at all. Unlike trapping, shooting or poisoning, it works. It is happening with extreme prejudice in Ireland at the moment.

There is a scientific term for this method. Pine martens.

Pine martens are predators native to Britain and most of Europe. They are members of the otter, badger and weasel family (the mustelids), that are at home both on the ground and in the trees. They are, to my eye, exceptionally beautiful. They look like sinuous chestnut cats with yellow bibs. Like many predators they turn out to be essential to the survival of healthy living systems.

It now seems that many exotic species, like grey squirrels, that appear to present intractable problems do so only because they are moving into depleted ecosystems. They become invasive and destructive because there is nothing left to restrain them. American mink, for example, are a major problem in Europe where there are no otters, proliferating rapidly and wiping out water voles, birds and other species. But when otters, which are highly territorial, move in, they drive the mink out. White-tailed eagles, which have recently been reintroduced to the Hebrides, but once lived throughout Britain, prey heavily on mink and, according to a study in Finland, keep them out of areas they would otherwise occupy.

There might be no grey squirrel problem – in fact there might be no grey squirrels here at all – had pine martens not been eliminated across most of their range, primarily by gamekeepers.

Grey Squirrel (Sciurus carolinensis) sat at edge of a mossy pond drinking with mirror reflection Photograph: Drew Buckley/Alamy

Grey Squirrel (Sciurus carolinensis) sat at edge of a mossy pond drinking with mirror reflection Photograph: Drew Buckley/Alamy

If you love grey squirrels, look away now, for Ireland has become a bloodbath. The North American rodents that once occcupied the whole island east of the River Shannon are now in full-scale rout, and the reds are pouring into the territory they have abandoned. While until recently the greycoats looked invincible everywhere, in around 20 years the frontier has shifted 100km to the east. At this rate, in another 20 years the last of them will have been driven into the Irish Sea, and Ireland will have been reclaimed by the reds. (No political metaphor is intended.)

So what’s going on? Well it now seems that the reason why grey squirrels never got past the Shannon is not that they couldn’t cross the river. They can swim, and there are plenty of places in which they could move through the trees without getting their feet wet. It’s because the far side of the Shannon was pine marten territory. And pine martens love grey squirrels – in the strictly carnal sense.

Red squirrels have a simple adaptation to pine martens: they are small and light enough to get to the ends of the branches, where the martens can’t follow. But grey squirrels, which did not co-evolve with these predators, are, by comparison, lumps: slower and heavier than the native species. They are also more terrestrial than the reds – more dependent for their survival on foraging on the woodland floor. Meals on legs, in other words.

As people in Ireland have mostly stopped killing pine martens, which are now legally protected, they have begun to recolonise their former ranges. And the grey squirrels appear to have vanished into thin air. You have to read the paper published on this phenomenon last year to believe just how rapid and comprehensive this process has been. But in case you don’t, here are some extracts…

Read the whole editorial here.

3 thoughts on “Let Nature Do Its Own Work

  1. Pingback: Panthers In Man’s Habitat | Raxa Collective

  2. All species have a value and a purpose and deserve our respect. Whenever we as humans decide to take matters into our own hands by tying to eliminate one species or another, we are harming the balance of nature, and we, as well as the natural world, will suffer the consequences.

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