Grey squirrel

Sciurus carolinensis


Photo credit: ©GBNNSS
Sciurus carolinensis  
  • The species preferred habitat is mature woodlands with a diverse understory however; in Ireland the species is common in agricultural lands, planted forests, scrub or shrublands, and urban areas.

Widely Spread Species:
  • Under Article 19 of Invasive Alien Species Regulation (1143/2014) Grey squirrel has been identified as a Widely Spread Species in Northern Ireland and as such, management measures have been put in place to minimise its impacts.

  • The grey squirrel is a larger tree squirrel than the native red squirrel. It has a distinctive long bushy tail and characteristic short front legs.
  • Colouration is known to vary with some specimens displaying ‘chestnut’ markings on paws, hips and face which can lead to misidentification. In winter the species displays a thick winter grey/silver coat on the upper side of the body with a white under side.
  • The total length of these squirrels ranges from 430-500 mm, tail length ranges from tail 210-240 mm, and generally is 400-710 g. in weight.

Download N.I.E.A. ID guide

Origin and Distribution:
  • Originated from North America but was introduced to Europe to ‘improve’ diversity of estates in the late 19th century and early 20th century.

  • Grey squirrel is considered the main threat to the endangered and protected red squirrel
  • They out compete the red for space and food and are also a known vector for the Parapox virus which can be fatal to red squirrels
  • Grey squirrels also cause economic loss to forestry plantations by stripping the bark of trees which can lead to tree die off

How did it get here?
  • Deliberate release

Is it found in Ireland or Northern Ireland?
  • Grey squirrels are found in most areas of Northern Ireland. 
  • More distribution information can be seen at the NBN Atlas NI.

You can help by reporting any sightings: @ the Centre for Environmental Data & Recording (CEDaR) - Or via the iRecord App.
Methods for prevention:
  • This species is very widespread across the island of Ireland, and total eradication is unlikely
  • Grey squirrel control is being concentrated in areas where there is the greatest chance that reds can be re-established
  • Focus remains on humanely controlling the species to prevent the spread of damage to habitats and other wildlife
  • Report all sightings to CEDaR

Current Legislative Position (Listed on 03 August 2016)
  • This species must not intentionally be brought into the Union; kept; bred; transported to, from or within the United Kingdom, unless for the transportation to facilities in the context of eradication; placed on the market; used or exchanged; permitted to reproduce, grown or cultivated; or released into the environment.
For further queries, you can contact the Invasive Non Native Species (INNS) Team in the Northern Ireland Environment Agency on 028 9056 9558 or Email:

Species Related Files:

Invasive Species Ireland

Invasive Species Ireland