I found an article in The Telegraph entitled, “Red squirrels are fighting back against the greys, experts claim.” It implies pine martens are saving the red squirrel as much as a grey squirrel trapping program is. The trapping program was introduced to reduce the grey population and give the reds a chance of survival.
Pine Martens To The Rescue
Apparently predatory martens are saving the red squirrel (see image above) as they are inclined to eat grey squirrels which they find nice and plump. The pine marten can catch the grey because they move slowly. This has been found in a study of red squirrels in Northern Ireland where the pine marten isn’t so rare as first thought.