Squirrel Ecology

The Red Squirrel (Sciurus vulgaris) is the only species of squirrel native to the British Isles. Red squirrels arrived in England across a land bridge from the continent as plants and animals re-colonised the country at the end of the last Ice Age (around 10,000 years ago). As a native species, the red squirrel is an integral part of our countryside and our national heritage.

Red squirrels live in trees, so are known as ‘arboreal’ mammals. Red squirrels can live in all types of woodland; in agricultural landscapes and sub-urban areas, they exploit pockets of trees and woodlands connected by hedgerows and other wildlife corridors.

Red squirrels will reach their highest population densities in mixed or broadleaf woodlands due to the diversity and availability of food. However, they are increasingly restricted to large conifer woodlands due to competition from encroaching grey squirrels.


Red squirrels are ‘granivore-herbivores’, meaning they primarily eat seeds from plants and trees but their diet can vary greatly throughout the year. Food is plentiful during the autumn and winter months when trees are rich with seeds and fungi are available.

However, food can be scarce during spring and summer, when their diets extend to include plant shoots, bulbs, flowers, wild fruits and even insects. Squirrels gnaw the scales off cones to get at the seeds within and discard the cores which you will find on the forest floor.


Squirrels are active all year round and do not hibernate. A squirrel lives in a nest called a ‘drey’ which comprises of a dense ball of interwoven twigs lined inside with soft materials like moss, leaves, grass and fir.

Dreys are usually located in the fork of a branch tight against the trunk, around two thirds of the way up the tree.

Breeding Season

The red squirrel breeding season starts with mating chases in January, and a first litter of 3 to 4 babies, called kittens, is born in March. If a female squirrel gains sufficient food over the summer months, she will have a second litter in July/August.

Like other mammals, the ‘kits’ are born blind, deaf and hairless and are totally dependent on their mother.

Kits start exploring their environment by the 7th week and are weaned by the 10th week. They will them start to fend for themselves but often remain close to their maternal drey. Juveniles usually disperse in the autumn, and sometimes in the spring.