The grey squirrel threat
The grey squirrel was introduced to Great Britain in 1876 and rapidly expanded its range replacing the native red squirrel. Grey squirrels carry the Squirrelpox virus which is deadly to red squirrels. They also compete for resources with the native squirrel and are better at extracting the protein from acorns.
Grey squirrels are the single major factor in the decline of the native red squirrel. They also pre-date birds nests, consuming eggs and nestlings, and cause significant damage to timber crops by bark stripping.
They damage trees by gnawing bark to get the sugary sap filled tissue underneath the outer layers. This tissue carries sugars produced in the leaves down to the stem and roots of the tree. Where squirrels ring bark a tree the flow of both sap and water is halted and the tree will either die or become stunted.
Grey squirrels are therefore controlled for a combination of reasons, and across the UK, even in areas where red squirrel populations were lost decades ago, grey squirrels are frequently being killed with Government grant aid. The Trust use live-trapping techniques to control greys in our project area, we do not use poison or any type of spring (kill) trap.
Captured grey squirrels are allowed to venture out from the wire trap into sacking that has been placed around the entrance. The squirrel is then moved into the corner of the sack and with the head positioned carefully within the corner, killed humanely by a single blow to the back of the head.
The best time of year for trapping grey squirrels is between March and September, when their natural food is scarce. During autumn the availability of tree nuts, berries and conifer seed significantly reduces the likelihood of catching grey squirrels. The Trust focus culling on the spring and summer months.
Anglesey once contained 3,000-4,000 adult grey squirrels but today less than 30 remain as a result of trapping operations. As red squirrels increased in distribution and abundance, the species crossed the Menai sea straits and colonized the coastal part of Gwynedd by Bangor. In 2011, the Trust started a trap loan scheme and hope to co-ordinate the clearance of a specific part of the mainland.
Those interested in learning more about grey squirrel control can:
Visit the BASC Trapping Mammals Code of Practice
Or, for detailed prescriptions and trapping guidance Download Forest Practice Note 4 (DEAD LINK)