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Citizen science survey keeping track of trio


Game of Cones: Red Squirrel versus Grey Squirrel

Game of Cones: Red Squirrel versus Grey Squirrel

Game of Cones: Red Squirrel versus Grey Squirrel

NUI Galway has announced the results of a citizen science survey of the present status of three mammals: the Pine Marten, one of our native woodland carnivores, and two squirrels, our native Red Squirrel and the North American Grey Squirrel.

The Pine Marten nearly became extinct in Ireland. However, populations started to make a comeback during the 1980s due to the combined impact of three main factors: the spread of forestry plantations, being granted full legal protection, and a consequent reduction in its persecution.

Grey Squirrels were introduced to Ireland early in the twentieth century and spread pretty rapidly to cover the eastern half of the island. The spread of the alien Grey Squirrel led to a decline in Red Squirrels as the greys out-competed them for food and are carriers of squirrel pox, a disease that they carry but do not suffer from but that is fatal for the reds. As a result, the Red Squirrel range contracted over several years and the native species struggled to survive.

The citizen science survey, led by NUI Galway and funded by the National Parks and Wildlife Service, was a cross-border collaboration with the Ulster Wildlife and Vincent Wildlife Trust. The survey set out to find how all three mammals are now faring.

Interested citizen scientists recorded details of their sightings of the trio under scrutiny. Over 3,000 records were received. The results show that Pine Marten populations are continuing to increase and spread, Grey Squirrel populations are in decline and Red Squirrel numbers are bouncing back.

Pine Martens hunt and eat squirrels. They find it easier to catch the bigger and bulkier Grey Squirrel than the smaller and lighter Red Squirrel that can retreat to the safety of the lightest tree branches. Our two native species can co-exist; not so the Grey Squirrel and the Pine Marten.

As a result, since the previous survey in 2012, Grey Squirrels have now functionally disappeared from counties Fermanagh, Monaghan and parts of Co Meath and Co Kildare. However, like rats, they continue to thrive in urban areas of Dublin and Belfast. Red Squirrel sightings have increased considerably, and the species has returned to parts of the Midlands where it had ceased to exist.

Full details of the 'All Ireland Squirrel and Pine Marten Survey 2019' are presented in Irish Wildlife Manual No 121 that can be downloaded from the National Parks and Wildlife Service website at

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