Pine marten could hold key to checking rise of grey squirrel
The grey squirrel is a typical example of the danger of introducing a new species of wild animal into the environment. The Irish population originates from a single introduction at Castle Forbes, Co Longford in 1911, and in the ensuing century their numbers and range have exploded alarmingly.
The grey squirrel is typically twice the size of our native red, more omnivorous and with a much greater appetite. Coupled with its competitive success against the red, it transmits a disease – the squirrel pox virus – which is relatively harmless to themselves but has an 80pc mortality rate for reds that contract it.
The grey really does have the capacity to threaten the native red with extinction, and it does great harm to our trees as well.
Grey squirrels strip the bark, predominantly from broadleaf trees, and feed on the sap. The damage leads to discolouration of the timber (and a significant drop in quality and consequential financial loss).
The weakened trees are also susceptible to wind-snap, and exposure to disease and fungal attack.
Bark stripping is most prevalent from March to June, and the principal species attacked are the softer-barked broadleaves such as beech, sycamore and maple, though in the absence of these they will turn their attention to species such as oak, ash and Scots pine.
The damage can occur when the trees are between six and 40 years of age, so even well established plantations are vulnerable to attack once greys have infiltrated an area.