[2] Genetic studies indicate that another, S. v. hoffmanni of Sierra Espuña in southeast Spain (below included in S. v. alpinus), deserves recognition as distinct.

In western and southern Europe they are found in broad-leaved woods where the mixture of tree and shrub species provides a better year-round source of food.

In most of the British Isles and in Italy, broad-leaved woodlands are now less suitable due to the better competitive feeding strategy of introduced grey squirrels.

The squirrel makes a drey (nest) out of twigs in a branch-fork, forming a domed structure about 25–30 cm (9.8–11.8 in) in diameter.

A Swedish study shows that out of 600 stomach contents of red squirrels examined, only 4 contained remnants of birds or eggs.

It often rests in its nest in the middle of the day, avoiding the heat and the high visibility to birds of prey that are dangers during these hours.

During the winter, this mid-day rest is often much briefer, or absent entirely, although harsh weather may cause the animal to stay in its nest for days at a time.

[citation needed] No territories are claimed between the red squirrels and the feeding areas of individuals overlap considerably.

[citation needed] Mating occurs in late winter during February and March and in summer between June and July.

Juvenile red squirrels can eat solids around 40 days following birth and from that point can leave the nest on their own to find food; however, they still suckle from their mother until weaning occurs at 8 to 10 weeks.

[28] Outside the UK and Ireland, the impact of competition from the eastern grey squirrel has been observed in Piedmont, Italy, where two pairs escaped from captivity in 1948.

Fewer than 140,000 individuals are thought to be left in 2013;[16] approximately 85% of which are in Scotland, with the Isle of Wight being the largest haven in England.

The population decrease in Britain is often ascribed to the introduction of the eastern grey squirrel from North America,[30] but the loss and fragmentation of its native woodland habitat has also played a significant role.

[32] Subsequent reintroductions into broadleaved woodland followed and today the island has the single largest red squirrel population in Wales.

Brownsea Island in Poole Harbour is also populated exclusively by red rather than grey squirrels (approximately 200 individuals).

In 2008, the Scottish Wildlife Trust announced a four-year project which commenced in the spring of 2009 called "Saving Scotland's Red Squirrels".

[38] On the Isle of Wight, local volunteers are encouraged to record data on the existing red squirrel population, and to monitor it for the presence of invasive greys; as the red squirrel is still dominant on the island, these volunteers are also requested to cull any greys they find.

[42] Research undertaken in 2007 in the UK credits the pine marten with reducing the population of the invasive eastern grey squirrel.

"Ekorr'n satt i granen" (The Squirrel sat in the fir tree) is a well-known and appreciated children's song in Sweden.

Charles Dennim, protagonist of Geoffrey Household's novel Watcher in the Shadows, is a zoologist who studies and writes about red squirrels.

In Norse mythology, Ratatoskr is a red squirrel who runs up and down with messages in the world tree, Yggdrasil, and spreads gossip.

[52] Red squirrels are a common feature in English heraldry, where they are always depicted sitting up and often in the act of cracking a nut.