Scientific report
All-Ireland Squirrel and Pine Marten Report
Species Red Squirrel
Facts about red squirrels
- English/Irish names: Red Squirrel/Iora rua
- Scientific name: Sciurus vulgaris
- Number of young: Between 1-6 kits born in spring
- Diet: Seeds and nuts of various trees
- Habitat: Woodland — hazel, beech and Scots pine trees are preferred
- Photos: Banner photo ©Lizzie Croose; Photo (R) ©Linda Priestley
Identification
Female |
Male |
|---|---|
| Length 18-20cm; Tail length 17.5cm; Weight 350g | Length 18-20cm; Tail length 17.5cm; Weight 350g |
- Ear tufts which become larger in mid-winter and disappear in the summer.
- A large bushy tail almost as long as their body.
- Red in the summer and darker brown/ grey in the winter. White underside.
Photo: ©Linda Priestley
History of the red squirrel in Ireland
The red squirrel is a native species that is thought to have been present in Ireland since before the last Ice Age.
It is dependent on woodland habitat and has suffered several population troughs, including almost complete extinction in the 17th century due to widespread deforestation. The current population mainly derives from reintroductions that took place in several locations during the 19th century.
Photo: ©Ruth Hanniffy
Distribution and status
The Irish red squirrel population is in recovery and was classified as Least Concern in 2019. According to the All-Ireland Squirrel and Pine Marten Survey Report 2019, the species is now recorded in every county, and during the survey the number of sightings increased compared to previous surveys conducted in 2007 and 2012.
The west of Ireland remains a stronghold for the red squirrel, and it is also commonly observed in several other counties. It was most frequently recorded in County Cork and County Wicklow, regions where the species was once considered at risk. Additionally, the red squirrel has begun to reappear in areas where it had long been absent. It remains absent from parts of County Meath and County Louth, though current trends suggest natural recolonisation may occur in these regions over time.
Further afield, the red squirrel has one of the broadest natural ranges of any squirrel species, spanning from Ireland to Japan across Europe and Asia.
There are two species of squirrel in Ireland: the native red squirrel and the non-native grey squirrel.
Red squirrels are noticeably smaller, weighing about half as much as greys. They can be distinguished by their long ear tufts and fur colour, though some overlap occurs; grey squirrels may appear brown-red in summer, while red squirrels can take on a greyish hue in winter, sometimes causing confusion.
Red squirrels spend most of their foraging time in the tree canopy, while grey squirrels are more frequently seen feeding on the ground. Reds are particularly elusive, often keeping to the far side of a tree trunk to avoid detection. In contrast, the bolder grey squirrels tend to be less wary of humans.
Red squirrels can be found in coniferous, deciduous, and mixed woodlands.
Red squirrel population densities fluctuate annually, mainly depending on seed availability. A diverse mix of tree species, resulting in multiple seed sources, provides a more suitable habitat for red squirrels.
Squirrels build nests, known as dreys, which are round structures made of sticks and foliage, typically positioned against tree trunks. They may also nest in tree hollows or within dense ivy. A single squirrel will use multiple dreys and may share them with others. While squirrels are not territorial, each individual has a preferred area within their home range, which they may defend according to a linear social hierarchy. Population densities rarely exceed 1.5 squirrels per hectare.
Red squirrels feed mainly on tree seeds, although they can eat fungi, fruit and buds as they become available in the woodland.
Red squirrels do not hibernate in winter. Instead, they rely on food they have stored, such as buried caches of nuts and stored fungi. Their foraging and caching behaviour helps to disperse seeds, contributing to forest regeneration.
Red squirrels typically begin breeding in January or February, with males chasing females and the most dominant individuals having the greatest success.
Following a gestation period of five to six weeks, females give birth to a litter of one to six kits. The young are born blind and hairless, remaining dependent on their mother until they are fully weaned at around seven to ten weeks.
In years with abundant seed availability, breeding can start early, allowing females enough time to raise a first litter and produce a second in early summer. Some young may stay with their mothers over the winter before dispersing.
Young squirrels begin breeding at around 13 months old, with breeding success improving with age. Older females are more likely to produce second litters, while older males have a higher chance of winning breeding chases. Mortality is highest among juveniles, with only 30–50% reaching breeding age. Those that survive can live up to six years in the wild and even longer in captivity.
Grey squirrels are one of the main causes of declines in red squirrel numbers. Although there is no direct aggression between the two species, there is severe competition for food resources, and grey squirrels carry the squirrel pox virus, which is almost always fatal to red squirrels.
Other threats to red squirrel populations include loss of woodland habitat and road traffic collisions.
The Red Squirrel is protected in the Republic of Ireland under the Wildlife Act (1976) and Wildlife (Amendment) Acts (2000 & 2010), and in Northern Ireland under the Wildlife (N.I.) Order of 1985.
Further reading