Before humans started cutting down the forests of the UK, the pine marten was likely one of the most common carnivores in the UK. This voracious arboreal hunter is the reason that our resident squirrel is so acrobatic – these skills would likely be tested every day.
Indeed, pine martens are less widely spread in the USA which is likely one of the reasons that grey squirrels are so incapable of surviving alongside pine martens. Thus, in the UK we have this perverse situation within the UK, where the only refuge of the red squirrel (apart from small islands which can be cleared more easily) are areas of the country where pine martens also survive on.
In the UK, it has been long known that pine martens survive in Scotland. Protection of their forests must improve if we are to hold onto them for longer.
Food sources in conifer plantations tend to be smaller, limited to small cones and such like. As such, this suited the smaller red squirrel more than the invasive grey. However this has recently been thrown into doubt.
Where as, in broadleaf tree plantations there are a variety of food sources for pine martens and so red squirrels will not be exclusively predated, in conifer forests with less food to find red squirrels are hunted more often.
This research is based on 5 years of observations from the public and camera traps. It was carried out in northern Ireland, and looked at pine martens red and grey squirrels.
In natural woodlands there is a diverse range of prey and plenty of refuges for red squirrels, however in conifer plantations pine martens will eat far more squirrels because there is little else for it to find.
We therefore need to stop replacing large areas of natural wood with plantations.
If this is true, then the pine marten has even more pressure on it, as it must drive the grey squirrel out so reds can survive. A recent study of grey squirrels dna shows that the UK population relies far more on humans. Far from colonising the country they appear to have been moved by humans and installed in new parts of the country on many occasion. One example, showed this by the fact that the grey squirrels around Aberdeen appear to have originated with the population around the new forest.