Irish Squirrel Survey 2012. Irish Wildlife Manuals, No. 89

The 2007 all-island survey of squirrel species in Ireland showed that the range of the invasive grey squirrel covered the eastern half of the island and had negatively impacted the distribution of the native red squirrel. The red squirrel, although generally widespread, was largely absent from areas where the grey squirrel was well established. The 2007 survey noted for the first time that the grey squirrel was now absent from some areas in the midlands of Ireland where it had previously been common. Some survey respondents anecdotally linked the absence of grey squirrels to the resurgence of the pine marten, a woodland-dwelling carnivore, in the area. A comprehensive survey of woodland owners and workers, other stakeholders and the general public was conducted to update the distribution maps of the two squirrel species, and the pine marten. Responses were confined to those received in 2012 and encompassed all counties in the Republic of Ireland and Northern Ireland, including records received during three regional surveys conducted by the authors in the midlands, south and southwest, and west of Ireland. New up-to-date distribution maps were generated for all three species of interest using the 2378 accepted responses. Since 2007, the grey squirrel has retracted in range in a broad area that covers several midland counties and this decline is believed to be a result of a strong negative association between the grey squirrel and the recovering pine marten population as identified by Sheehy and Lawton (2014). The red squirrel had returned to some parts of the island from which it was previously recorded as absent. In other parts of Ireland however, the grey squirrel continues to act as an invasive species, extending further its north-western, south-western and south-eastern range. These new distribution maps provide vital information for the forestry industry and wildlife conservation bodies on the protection of Irish broadleaf trees from grey squirrel mediated damage and the conservation of the native red squirrel. The authors provide recommendations for future actions to manage the impacts caused by the invasive grey squirrels.