Ecology

Red squirrel by Gary Bruce Highland Photographer


Eurasian red squirrel, Sciurus vulgaris

Red squirrels are the UK’s only native squirrel and recolonised the land after the last ice age. Their survival is now threatened - mainly by competition and disease transmission by grey squirrels.


Animal: mammal


Length: 18-24cm


Tail: 17-18cm


Weight: 100-350g


Average lifespan: 2-5 years


Physical features: coat and tail vary from red to black, body has a pale underside - but fully melanistic and albino varieties exist. Often with tufts on the ears, which they moult at different times of year.


Native range: Europe and Siberia.


Habitat: woodland, heathland, moorland, parks, gardens - they create dreys (nests) of interwoven twigs, lined inside with soft materials such as moss, leaves, grass and fir.


Diet: mainly seeds and nuts, supplemented by plant material, fruits, fungi and occasionally bird eggs.


Breeding: mating begins in January and a litter of three to four kittens are born in March. A second litter can be born in July/August if females have enough food.


Population: ~140,000, down from 2.5 million over 100 years ago.


Status: UK protection under the Wildlife and Countryside Act, 1981. Priority Species in the UK Post-2010 Biodiversity Framework. Classed as near threatened in England, Wales and Northern Ireland; locally common in Scotland.


Threats: competition from invasive non-native grey squirrels, diseases - especially squirrel pox linked to grey squirrel spread, habitat destruction, road traffic accidents, predators.

Grey squirrel by Osman Köycü


Eastern grey squirrel, Sciurus carolinensis

Grey squirrels are not native to the UK. Originally from North America, they were intentionally introduced to sites in England and Ireland between 1876 and 1929, then established and spread.


Animal: mammal


Length: 24-29 cm


Tail: 19-24 cm


Weight: 400-650 g


Average lifespan: 2-5 years


Physical features: generally silver-grey coat, sometimes with brown shading to face and feet, and a pale underside - but fully melanistic and albino varieties exist. Tail has an outer fringe of white hairs.


Native range: eastern North America


Habitat: woodland, heathland, moorland, parks, gardens - they create dreys (nests) of interwoven twigs, lined inside with soft materials such as moss, leaves, grass and fir.


Diet: mainly seeds and nuts, supplemented by plant material, fruits, fungi and occasionally bird eggs


Breeding: mating begins in January and a litter of three to four kittens are born in March. A second litter can be born in July/August if females have enough food.


Population: estimates of 2.5 million, but there is no definitive figure.


Status: classed as an invasive non-native species in the UK and an invasive alien species in Europe. It was moved outside its natural range by humans and has negative consequences for native biodiversity and the economy.