Red Squirrels Welcome an Unlikely Hero in Britain
Pine martens are populations are slowly rising in areas of Britain, and red squirrels are flourishing with them
A rodent-eating predator may seem an unlikely hero for a red squirrel, but the return of the pine marten is proving a valuable asset in their recovery. Pine martens, a member of the weasel family, are being reintroduced to certain areas of Britain, with small populations in the New Forest, northern England and north Wales, and larger populations in Ireland and Scotland. At Kirkcudbright Training Centre, the Ministry of Defence is now involved, placing den boxes in trees to help the predators flourish. Pine martens used to be widespread across the British Isles, but due to habitat loss and predation by humans, they all but died out during the 19th century. Now, their return is being celebrated by ecologists nationwide.
But how does this benefit red squirrels? The answer is simple: pine martens prey on grey squirrels. According to the Department of Agriculture, Environment and Rural Affairs (DAERA), the grey squirrel is all but a death sentence for the reds. This is because grey squirrels not only outcompete the reds for food, but also carry disease:
‘When the grey squirrel arrives in a red squirrel area, the red squirrel population usually disappears within 15 years. The grey squirrel outcompetes the red for food, space and carries a disease, called the squirrel pox virus. This disease kills the red squirrel but has no known lasting effect on the greys.’
Photo by John Thorne
Grey squirrels are not native to Britain – in fact, only a small number were brought over from America as an ornamental species for the grounds of stately homes. By the time the damage they were causing was noted and it became illegal to release them, their populations were already established.
It is still unknown why the grey squirrel is the pine marten’s preferred food source, but some theorise that, as red squirrels and pine martens evolved together, red squirrels are more wary of the danger. Before now, grey squirrels have never had a predator in Britain and spend much more time on the ground, so they are being caught unawares. The other theory is that being a much larger animal, grey squirrels simply make a better meal. Either way, both the red squirrels and the native trees are benefitting from the pine martens’ arrival.
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